One of the papers appears to be a fragment of an envelope, covered front and back with writing. Another is a small slip of paper, with some words and numbers written on it, and then of course there is the flower. I also found an old bookseller’s catalogue entry.

I wonder if anyone can identify the thing that looks to me like a postmark?

A fragment of an envelope was used for a long division sum

Here is the back of the envelope, which has not a calculation but a list of titles:

The other side of the fragment of paper was used to write a list

I am not good at reading this sort of handwriting, which fell out of fashion in England many years before I was born, but here is an attempt to transcribe it; contact me with errors and I’ll update it.

1. Clergymans Assistant
2. Haddon on the Creed
3. Stillingfleet’s Orig. Sacr.
4. Burnet on the Art
5. ??? on the Gospels
6. Ridley’s Sermons
7. Barrows Sermons 2 Vols
8. Homilies
9. Potters Theological Works
10. Burtons Sermons
11. Hornes Works 7 Vols

Since I have been making an online edition of Chalmers’ Biographical Dictionary (1812—1818, 32 vols), I thought I’d look these up.

The Clergyman’s Assistant could be The Sick Man’s Companion or the Clergyman’s Assistant in visiting the Sick; with a Dissertation on Prayer by William Dodwell; there are other possibilities, but the long ess indicates a likely time before 1830 (it was mostly discontinued in printed books in Britain some time before 1810, but one has to imagine that people did not immediately revise their handwriting)

Haddon on the Creed, I think may actually be Peasson, I’m not sure. I can’t read it.

The Origines Sacræ is by Bishop Edward Stillingfleet.

Burnet on the Art is probably Gilbert Burnet and his Exposition of The Thirty-nine Aryicles of the Church of England, on the Articles of Faith, an early Working-Group compromise.

Ridley’s Sermons is possibly Nicholas Ridley, the famous contemporary of Cranmer, but I see that Dr. Gloster Ridley gave Eight Sermons at Lady Moyer’s Lecture, published in 1742.

Barrow’s Sermons are probably by Isaac Barrow, 1678. Chalmers (c. 1812) says that Dr. Barrow’s sermons are yet admired for the style and
moral sentiment. (see linked page).

Homilies, I have no idea.

Potter’s Theological Works are the collected writings of Archbishop John Potter (no relation of Harry I think), published in 1753 as The Theological Works of Dr. John Potter &c. containing his Sermons, Charges, Discourse of Church-government, and Divinity Lectures. Short titles ftw.

Burton’s Sermons would probably be John Burton, whose Sermons were published in 1764 and 1766 respectively.

Wow, almost done!

Bishop George Horne ‘s Works were collected in 7 volumes and published by one Jones of Nayland in 7 vols in 1799.

Hmm, and I mentioned the pressed flower:

The pressed flower

And finally, here’s the obverse of the pressed flower:

pressed flower, the other side up.

This idea is not currently compatible with the way namespaces work. in XML, you have to do one of two things to introduce a new namespace; either:

1. Use an xmlns pseudo-attribute on the element you want to introduce the new namespace, or,
2. Use a DTD to supply such an attribute, by giving it a default (or fixed) value.

Now, HTML 5 gets rid of the idea of a DTD: there’s no DOCTYPE declaration, for example, with SYSTEM and/or PUBLIC identifiers. And there’s no sign that the browser vendors are willing to revisit that decision.  So that leaves us with an explicit xmlns pseudo-attribute, and that also doesn’t sit well with the HTML 5 people.

Jumping up and down and yelling at HTML 5 people to use more syntax so that HTML 5 looks more like XML isn’t working. But wait, can we change XML in some way so that we have a way to describe this default namespace behaviour? Let’s say it’s OK to do this in XML, and find a way to make it OK, and then it won’t bea problem, right?

Well, namespace declarations are not the only issue, it turns out, but bear with me for a moment, let’s see how far we get with Unobtrusive Namespaces, and then we’ll take it even further and make Imaginary Namespaces, which address this need of HTML 5.

The idea of Unobtrusive Namepsaces, then, is to take away as much of the syntax as possible—ideally, all of the syntax—from the document, much as Unobtrusive Javascript did. Let’s imagine that an XML processor (I’ll come back to HTML browsers in a moment) understands an attribute nsd="svg", and that the meaning of this attribute is that a particular namespace definition is to be used. That namespace definition is a URI (a relative URI here), with the understanding that the well-known URI for the HTML namespace definition is built in to the Web browser and need never be loaded. But what does it do?

A namespace definition can do any of:

1. give a list of elements, and associate namespace URIs with them
2. define an element/attribute pair, to put the named attribute into a different namespace (this is to work round what I see as a deficiency of XLink, as used e.g. in SVG)
3. refer to another namespace definition

This combination of features lets you make namespace mashups; it also is enough that we can define the HTML 5 behaviour. Even better, you can define your own extensions, use them with no explicit namespace prefix, and, if they later become part of HTML, your documents will continue to work unchanged! How cool is that?

Of course, a Web browser doesn’t want to fetch an extra file. This is where the concept of Imaginary Namespaces comes in.  With Imaginary Namepsaces, we write into a spec such as HTML 5 the namespace definition file that an implementation must use, or must behave as if it uses. But the user agent doesn’t actually need to load the file. After all, the whole idea was to change XML rather than asking HTML to change.

So, I’m proposing the following:

1. A default namespace definition file for HTML 5 to be mentioned in the HTML 5 specification.
2. Web browsers continue to behave in the same way as now.
3. For added brownie points, Web browsers would fetch namespace definition files if they are mentioned (and are not in the browser’s cache, of course). However, such files would only ever augment the standard definition, so that the browser could render the document up to the first unknown attribute or element without waiting for the namespace definition file to load.
4. XML processors could load the namespace definition files, or, one could use XSLT (or XQuery) to read the namespace definition file and produce XSLT that, when ran, would add the correct namespace nodes to a document. In this way, one could validate the document and process it with existing XML tools.
5. Existing namespace syntax is in no way affected by this proposal. Existing XML documents would continue to work exactly as they do now.
6. Ideally, Web browsers should also understand XML namespace syntax in documents, for the sake of people using e.g. mathml or SVG editors, or trying to serve XHTML as text/html for compatibility (= broken software workaround) reasons. But my proposal isn’t about existing namespace syntax, it’s about Unobtrusive (and Imaginary) namespaces.
7. If a namespace definition file actually listed all the names in a given namespace, you could use it to validate your use of a namespace in some way. That’s not a deliberate goal of this proposal, but it’s a way that some people have said they’d like to use it, as a sort of very light-weight schema language.

Finally, what should a namespace definition file actually look like? Here is one proposal; I’m open to other syntax, as long as people working with namespace definitions do not need to understand traditional XML namespace syntax! It’s this requirement, for example, which seems to rule out the related ISO DSRL draft.

<nsd>
    <html>
        <uri>http://www.w3.org/1999/xhtml</uri>
        <svg>
            <uri>http://www.w3.org/2000/svg</uri>
            <attribute>
                <name>href</name>
                <uri>http://www.w3.org/1999/xlink</uri>
            </attribute>
        </svg>
    </html>
</nsd>

I’m not committed to this syntax; I’ve tried to make it simple, reasonably redundant so that you can get good error messages, and only just powerful enough to do what’s needed. The syntax I proposed at Balisage in Montreal was slightly more complex; you can see it linked to one of the slides I used (that presentation was aimed at suggesting to an XML audience that we could improve namespaces by making them useful and practical, but it was not written for Web developers, who don’t need to be persuaded that there are problems with namespaces today, and perhaps do need to be persuaded that it’s worth having consistent rules between HTML and XML).

So that’s it. It won’t affect JavaScript APIs, it won’t give Web browsers ways to understand unknown markup if they don’t have any underlying code, but it does give a way to identify extension points in a way that lets them become part of the standard in the future, and, for authors, it reduces the cost of using namespaces.

Thoughts?

[note: comments are moderated for spam control  purposes only]

I had to do a lot of learning, and there were some really obvious things that the manuals didn’t say, but that had me baffled for a while, so I thought I’d share some of those basics!

What on earth is a dSLR?

In my case it was easy because I was given a gift certificate for Future Shop, and they only sold one digital SLR camera, the Canon Digital Rebel.  Luckily this is a really good camera, and an excellent first choice, and I happend to know that already.

More likely, you’ll be faced with a bewildering choice.

The SLR has three main features that set it apart. The first is that when you look through the viewfinder, you’re looking through the actual lens. Newer dSLR cameras have “live view” in which the LCD display also looks through the lens, although usually you can’t have both live view and the viewfinder work at the same time, because the SLR uses a moving mirror to choose whether the light from the lens goes into the viewfinder or onto the sensor (the digital “film”). For professional shots, it’s essential that you get a good idea of what’s going to be in the photograph, so this feature is really important.

The second feature of the SLR is that you can swap lenses.  The entire lens unmounts and you put on a different one.  There are literally hundreds of lenses to choose from, which of course paralyses me totally.  It does mean you can get a telephoto (long-distance) lens, and also a macro lens; the point-and-shoot Casio camera had fabulous macro (close-up) performance, but absolutely terrible long-distance results.

The third feature is that the lens is bigger, and so is the sensor.  Some of the newer point-and-shoot cameras are changing this, but what it means for now is that the pictures from a dSLR are massively clearer and sharper than you’d ever imagine possible.  Of course, you can go up from the dSLR to a medium or large format camera and get even better, but that’s another story!

So, a digital single-lens-reflex is an SLR camera, so that you look into the viewfinder and see through the lens. It has interchangeable lenses, and it usually has much higher picture quality than a point-and-shoot camera.  It’s also usually much bigger and heavier, and you’ll be noticed more, and you might find you can’t take it into rock concerts, or that you can take it into museums because they trust you to turn off the flash.

Choosing a dSLR

The first thing to say here is, for all intents and purposes, if you are not a professional photographer, forget about “megapixels,” “auto-red-eye-elimination,” “face detection” and all the other features touted by the tiny cameras.  Buy a dSLR so that you can take professional-quality photographs, and so that you can do photographic art, but not so that you can quickly whip out a camera and snap a high-school friend on the bus.  A lot of pro photographers carry something like a Casio Exilim pocket camera for exactly that pupose!

The main entry-level dSLR cameras all have roughly comparable image quality. You can make an A4/US letter-sized print with any of them: 8 megapixels is about enough for that.  The advantage of more pixels is that you can use your favourite image editor (e.g. gimp) to choose a smaller portion of an image, and print that instead. You can also do more processing without degrading the quality.

The main things to look for are

1. Someone local who can repair the camera, sell you accessories, and make you feel inferior.
2. Compatibility with other equipment.

Let’s take these one at a time. first, someone local. It’s usually best to buy from a local shop, because you help the local economy, you help keep the shop in business, and the shopkeeper probably knows more about the camera than someone working in some big box chain. Cameras are hard to buy by mail order because shipping can damage them, so for my part I’d always go somewhere local, although, as I said at the start, I actually bought mine at a big box store. At least it was a local franchise.

Second, compatibility. Often people have older SLR cameras, and want to use the lenses.  It turns out that if you want to use a variety of lenses from other cameras, especially film cameras, your best bet is likely a Canon dSLR. You can use Nikon, Olympus, Canon, Pentax, and many more lens brands, by getting adaptors.  You might think this would work for any camera, but it turns out not to. You can only get a useable adaptor to go from a larger camera to a smaller one. The technical bit is the distance from the end of the lens to the film (or sensor in a digital camera). You have to end up with the right distance, or the lens won’t focus properly.  The Canon Digital Rebel series (EOS), for example, has a smaller distance between lens and sensor than the Nikon digital cameras. This means that if you use a Nikon lens on a Canon, the adaptor is a couple of mm (about a tenth of an inch) thick, and spaces the lens properly, as well as containing electronics to make the focusing work better.  But if you tried to use a canon lens on a Nikon, the Nicon camera is too big, and the lens can’t get close enough to the sensor without some serious modifications to the camera.  It’s possible to correct for this with glass,but that reduces the image quality and makes the whole thing pointless in most cases.

So if you’re after the ability to use lots of lenses, right now Canon is the best bet, it seems.  But, is that really important? The newer dSLR lenses have image stabilisation, which counteracts movements of your hand when you’re taking the picture, and helps reduce blur.  Some digital cameras have image stabilization built in, but the higher-end manufacturers point out that different lenses need different stabilisation, put the technology in the lenses, and charge you more money for a better result.  So with a Canon, with image stabilisation in the lens, you’re much less likely to want to use an older lens, than with a Pentax with image stabilisation in the camera.

Choosing a Lens

When you buy your camera, it will probably come with a dreadfully cheap plastic lens.  If you find a good dealer, you can get the camera with an upgraded lens, or without a lens at all, and buy the lens separately. Do it!

Lenses have three main things you need to know.

1. The maximum aperture
2. The focal length
3. The quality (including whether it’s stabilised)

The aperture is described as a ratio, with lower numbers meaning a wider ratio and a better lens.  You should aim to get at least one lens with a ratio of 2.8:1 or better (i.e. lower, 2.8:1 is much better than 3.5:1). These are also called f-stops, and 2.8:1 is written as f/2.8, so look for an f/2.8 lens.  I’ll explain why in a bit.

The focal length is the zoominess.  An 18-180 mm lens is a 10× zoom.  The kit lens is usually 18-55mm, which is about a 3× zoom.  A 300mm lens starts to be useful for photographing wildlife, although you’ll also want a tripod and a remote shutter control so that you can be out of sight.

The 50mm f/1.8 lens that both Canon and Nikon sell is the best value lens.  With a really wide aperture, you can get good shots in low light (even moonlight, with a long exposure) and you can also play with “depth of field” to get the subject in focus and a blurry background, excellent for portraits.

On lens quality, you generally get what you pay for, but read some reviews.  The Nikon Nikkor lenses, and the Canon “L” series lenses, are fabulous, but expect to pay over a thousand dollars for one lens. Image Stabilisation is essential (i’d say) for a walk-about lens, and less important for macro photography or with a tripod.

So, I’d get the 50mm f/1.8 lens, and maybe one of the third party “super zoom” lenses that go from 18 to 180 or even 18 to 300mm, to start with, today.  I actually have the canon 17-85mm lens with image stabilisation, because it’s the best I could afford; I also have the 70-300 mm lens, although I’d like to upgrade that one day, and the 50mm f/1.8 lens. The 50mm lens was about $100, and i got the 17-85mm lens used at a camera store (Peace Camera, in Raleigh, NC, in fact).  The super-zooms with image stabilisation from Tamron and Sigma are new since I bought my camera, though.

Taking a Shot

OK, so you’ve got the camera, and you want to take a shot, what do you do? The manual for my camera didn’t say, really, and I had to work it out!

1. Take off the lens cap!
2. Turn on the camera (I leave my camera on for weeks at a time; the batteries last for ages) and, for now, put it in “Programmed” or “Auto” mode, “P”.
3. Point the camera at something interesting, such as a friend’s ankle.
4. Look through the viewfinder
5. If you want to zoom, you turn the big ribbed part of the lens with your hand. This really stumped me at first, I was looking for a button, and the manual never said how to zoom with a digital SLR! All you do is turn that part of the lens, and it zooms (if it’s a zoom lens: the 50mm f/1.8 I mentioned earlier does not zoom at all!)
6. Press the shutter button half-way
7. You should see one or more red dots light up in the viewfinder. This is showing you that the picture is in focus where the dot is lit.
8. Holding the camera steady (elbows together can help), press the shutter button down the rest of the way. The loud click is not a recorded sound: it is because an SLR camera has a mirror or prism in it to make the light go into the viewfinds, and that must be moved out of the way to take the photo.

Of course, there’s a bit more to it than this when you get technical, but you can take really good photos like this.

colour image as scanned (detail)

There are three things I’ll need to do to make this image useful: smooth out all those dots, scale down the image, and get rid of that yellow fringe.

We must actually do them in the opposite order: first the fringe, then smooth the dots, and then finally scale down.   That’s because you must always work at the highest resolution so you don’t lose detail, and because the smoothing will make it harder to fix the fringe.

The yellow fringe is only on one side of this brave warrior’s head.  He stands there oblivious to the fact he has been badly printed!

To understand what’s going on, we need to remember how colour printing like this works.  Four separate images were printed on top of each other: a black one (called K), a red one (called M, for Magenta), a Yellow one (Y) and a blue one (called C, for Cyan).  Four images, each printed with a single colour.  The names of these four images, shuffled around, give us CMYK, the name for four-colour images.  The inks have interacted with each other a little, but we will pretend they don’t, and use GIMP’s Colours/Components/Decompose menu item, choose CMYK, and end up with a new image with four black layers, one for each of the four colours.

That was a lot of words to describe something simple, but it’s easier to remember how to do this if you understand what’s going on.

Now we have our four black layers, we can move the yellow layer down a little.  You can do this using the sample image in this blog posting if you want to try it.  Go to GIMP’s layers dialogue (you can go to Windows/Dockable Dialogues/Layers if it is not showing).  Hold down shift and click on the eye to the left of the yellow-k layer, and then click on the name of the layer next to it, the yellow-k, so it’s selected.  Choose the Move Tool from the toolbox (or press the lower-case m key) and then, to move the yellow layer down 10 pixels, press the down-arrow key ten times.

You could try Colours/Components/Recompose now, but it wouldn’t work, so wait just a moment. First, we must right-click on that yellow-k layer in the layers dialogue, and when the menu pops up, choose Layer to Image Size.  This will add some transprent pixels to the top of the yellow layer and chop off the bottom, so that when we recompose, it will be lower.  Otherwise, GIMP shifts the layers back when it does the recompose.  OK, now you can do Colours/Components/Recompose.

The resultimg image is much better.  If you also move the magenta layer a little, you can get to something like this:

After adjusting the separated CMYK layers and recomposing

It’s still not perfect, but because the images are overprinted, moving the yellow layer won’t really make bits of yellow suddenly appear from underneath red: there will just be a bit of a smudge where the inks blended.

You might also wonder if the individual mis-aligned images might be rotated slightly.  if you wondered this you would be right, but we cant fix that here. If you try, you will generate lots of unwanted patterns because the little dots will make interference patterns and moiré effects. So move them only horizontally and vertically for now.  Later you get a chance to fix rotation, but it is much less effective.

The next steps are easy, and are just like normal scanning: use Filters/Gaussian Blur to get rid of the individual dots.  There’s some mathematics behind this, but for our purposes all that matters is that the dots vanish in the preview.

After blurring.

I used a radius of 9 pixels on this image, which was scanned at 800dpi (or 800ppi for confused pedants). Now I’ve got a really blurry soldier, perhaps after a few beers, but after I scale him down he will be sharp again.

Note that if you still have colour fringing from rotated mis-printing, you can now try separating into CMYK, rotating the offending layer or layers, using Layer to Image Size on the layer or layers you rotated, and then recomposing.  The blur that we just did will make it safe to rotate, but the separation won’t be as clean, so depending on the image, it might not work.

You might also want to improve the colours now – e.g. reducing saturation.

Back to getting smaller. To get a sharp image after a blur radius of 9, you’ll really need to scale to 33% of the original size or smaller.  I wanted to make a screen background at 1600×1200 pixels in this case, so that was about 30%, although smaller sizes will be sharper.

After making it smaller, you can see more of it!

Here is the result – since the image is smaller, rather than a small thumbnail I’ve included more of it, but if you’re using these images for practice, sadly you won’t get more of the picture come in from the edges when you scale down so yours will look a little different.At this size you can’t really see any remaining colour fringing from misaligned colour separations.

We can still improve ths colour in this image by reducing saturation (it’s actually best to do that before scaling down usually, of course), but all I’m going to do right now is Filters/Sharpen, to get a final result like this:

After sharpening

There’s still a bit of a magenta fringe above people’s heads in this example, so moving magenta down may have been worth it.

I used a Sharpness of 65, because a higher value brings back the rosettes a little.  It’s a tradeoff, but if you see dots again at this stage, you have to use undo right back to the blur, and redo the blur with a larger radius.  Note that Sharpen is likely to give better results than the unsharp mask that many people love. Unsharp mask tends to introduce halo effects around the lines in illustrations like this, but works well for some kinds of photograph. Try them both and see which works best for you.

The final image is (or will soon be) on www.fromoldbooks.org.

1. Some people report that a piece of opaque green paper placed behind the page will help reduce show-through; either that or black card seems to help.
2. Look at the image, using a magnifying glass if necessary, and see if it is made of lots of small dots, or is printed with solid areas of dots.  If the book is from before 1850 or so, colours are likely either to have been added by hand, perhaps with a water-colour brush, or in separate print runs of solid colour. If the book is after 1860 or so, there will probably be dots.  You’ll need this information later.  You might also want to note down the page number.
3. Make sure the page is flat on the scanner’s glass!  If necessary, weigh it down a little with another book. If you bend the book back somewhat you can loosen the binding a little, which helps.
4. If you are using Gimp, you can scan the image by going to the File menu and choosing Create, and under that xsane.  If you are using Photoshop it’s most likely under the File/Acquire menu.   For an image made of dots (screened) you will need much higher resolution than you might expect, because capturing the exact size and shape of each of those dots determines the amount of detail you will get in your final image.  You can experiment, but I find there is often a noticeable difference between 600 and 1200dpi, and always a noticeable difference between 300 and 600.
5. When you choose the area to scan (usually by dragging a rectangle), make the area a little larger than the image all round.  There’s no need to go wild here, as scanning too much will just eat up memory and disk space, but you want enough extra to give you room to rotate the image to make it perfectly level afterwards, and to make sure you don’t accidentally miss a bit if the preview isn’t accurate.
6. Your scanning software (e.g. xsane) will probably have a button to auto-adjust levels, and you should press it.  You want the darkest part of the picture to be black and the lightest part to be white (or nearly white) in the output.  I find that I have to increase the gamma to about 1.2 with xsane, though, to keep the detail.
7. Once you have scanned the image, you will want to save a copy.  I always include the page number, but since the book is still sitting on the scanner at this point, you can see why I suggested remembering the number!  I tend to use filenames like 0314-Taj-Mahal-raw.png for the original and 0314-Taj-mahal-cleaned.png for the version after I have processed it (which I am about to describe).
8. Now you have saved the image, you need to make it look like something you want to keep.  The first step is to check the colour range; in Gimp this is colours/levels, and you can use the auto button on that dialogue box to get a good first attempt.  It’s probably good enough for now, but if the colours go weird, choose reset and instead move the little triangles so they point to the upper and lower ends of the histagram. Now you have an image with colour values spanning the whole range; that’s important because as we process the image it means we won’t lose as much detail.
9. Next we remove the dots.  You can do that with a Gaussian blur.  (if there were no dots, you can skip this step).  Choose Filters/Blur/Gaussian Blur.  When the dialogue appears, make sure the preview is ticked, and move the slider to about 11.  For 1200dpi or higher you may need it to be 17 or higher.  Your goal is to find the smallest number at which you can’t see any dots in the preview.  Use the scrollbars (and resize the filter window too) until you find a part of the image that’s fairly light in colour, as the dots are most visible there.  Usually the dots are in clusters, called rosettes, and you need to blue enough that the rosettes are gone too.  Once you find that number, go one or two higher, so, if the rosettes (or at least the dots if you can’t see rosettes) are gone with a bur radius of 12 in the preview, you’ll increase the radius to 13 or 14.   Then press OK to blur the image.  It may take a while.
   Note: If your image has black line art and screened colour, you can experiment using selective gaussian blur to keep the black sharp.
10. Once the image is blurred, you can rotate it, if needed, so it’s upright.  This is easiest in gimp using the Rotate tool with the tool options set to reverse/corrective and the preview set to grid; then you can move the grid so it lines up with something horizontal or vertical in the image.   You can change the spacing of the grid lines in tool options to help the grid line up.  Choose Cubic for the rotation algorithm, because you don’t want to preserve detail here that is just a remnant of the dots.
    Note: if you rotate before you descreen, you will introduce new artefacts that are difficult to remove. So you do the blur first and then the rotate.
11. After rotating, flatten the image (rotate introduces transparency, which we don’t want here).
12. We are nearly done, don’t worry.  At this point, I’d save a new copy of the image with the -cleaned- in its filename, because we’ve done enough work that we’d be cross if there was a power failure and we had to start over.
13. Make sure the image fits in your window (c0ntrol-shift-E in Gimp) and decide how bad the colours look.  Use Colours/Curves and experiment a little.  Or use Colours/levels and use the “white point” eye dropper to click on part of the image outside the picture, where there is plain paper.  Your goal now is to get something that looks roughly like the printed original.
14. Optional step, but very wise: go over the image slowly, at 50% magnification, looking for things like dead insects or hairs or other things you want to fix, and use the clone tool as needed (with a soft brush) to get rid of them.
15. When you’re happy, save the file again.  Use PNG, because it’s lossless.
16. Now you have a nice clean descreened image, but it’s blurry and it’s too big.  No problem: scale it down!  Use image/Scale Image, and go down to, say, 25%, and the image will look much better.  If you want a really sharp image, scale down further, but remember to keep that cleaned PNG file at fill size.  Now, we’re nearly done!
17. After you downsize an image you often need to sharpen it, using Filters/Enhance/Sharpen.  Some people prefer unsharp mask, but I find that’s best for photographs rather than scans of screened prints of photographs. I also prefer to be subtle with sharpening, but again it’s a matter of preference.
18. You can save the smaller scaled-down image as JPEG; I find if there are isolated blobs of red that I need to use the 1×1 subsampling to keep the colour right.

With practice you can do all this fairly quickly. I find the slowest part is usually fixing any problems like hairs or stuff that falls out of the binding of some older books.  You know, $10,000 bills and ancient Roman golden rings. Or more likely tiny pieces of paper, string or leather.  Wipe the scanner glass between scans with a clean piece of kitchen paper, wiping gently always in the same direction, so that pieces of grit don’t make scratches.

Oh. If your image did not have tiny dots, but was printed solid, or if there was detail in the black

I’ll also be moving over my XML-related blog entries from W3C.