Block
Plate

The short version

You give it a picture. It reduces that picture to a small number of flat colours — one ink and bare paper, or up to six inks — and then checks the result against what lino can physically hold, at the size you intend to print. Everything happens on your own machine; no picture is ever uploaded anywhere.

Getting a good black and white

• Despeckle removes single-pixel dust while leaving edges sharp. Start here.
• Soften blurs everything a little, which simplifies fussy areas into shapes you can actually cut.
• Threshold is the dividing line: darker than this becomes ink. Auto picks a sensible starting point.
• Even out uneven lighting compares each part of the picture to its own surroundings rather than to one number for the whole image. If you photographed a drawing on a table lit from one side, this is the setting that rescues it.

Working in colour

The colours slider counts inks, the way you would describe a print out loud. A two-colour print means two inks — the paper is not one of them.

At 1 you get the black and white block described above. At 2 to 6 the picture is divided into that many flat colours instead, chosen from the picture itself rather than from a fixed palette, so what you see is what that photograph actually reduces to.

Leave one colour as bare paper is on by default. It holds one tone back as unprinted sheet, which is what happens at one colour anyway. Turn it off when the design covers the whole sheet and every tone gets inked.

The swatches under the slider show the colours found. The one acting as paper has a dashed border and is drawn in your chosen paper colour. Tap any other swatch to make that one the paper instead — useful on toned or dark paper, where the unprinted areas are not the lightest thing in the picture.

Block Plate stops at the picture. It will not tell you which block carries which colour, what order to print them in, or what ink to mix — that is Reduction Ladder, the next tool along.

The example

Try an example loads The Great Wave off Kanagawa by Katsushika Hokusai, about 1831. It is a good thing to practise on: strong shapes, plenty of fine linework to set the sliver warnings off, and large flat areas that threshold cleanly.

The print is long out of copyright and the Metropolitan Museum of Art has released its scan into the public domain, so it travels with the app. It is stored inside the page itself, which is why the example still works with no signal.

Working with the picture

Left and Right turn the picture a quarter at a time. This is worth doing before you print: a design that needs four A4 sheets one way round often needs only two the other. Turning changes what "printed width" means — it is always the width of the picture as you are looking at it — so check the sheet count underneath after you turn.

Compare lays the photograph over the design so you can see what has been lost. Tap it on and a divider appears down the middle — photograph on the left, block on the right. Touch or drag anywhere on the preview and the divider follows your finger. It is the quickest way to check whether a threshold has eaten something you wanted, and it turns itself off when you load a new picture.

Change picture swaps in a different one; Remove clears it and gives you the empty panel back. Your settings stay put either way, so a second photo can go through the same treatment without setting it all up again.

Mid-tones

A photograph is mostly grey, and grey is the thing relief printing cannot do. The three treatments turn grey into marks a gouge can make:

• Hatch — parallel lines that thicken as the picture darkens.
• Cross — the same at two angles. Reads darker and richer, cuts slower.
• Stipple — dots on a jittered grid, growing as the picture darkens. The most forgiving to cut and the most hand-made looking.

Solid black below and clean paper above set the band that gets treated. Everything darker is filled solid; everything lighter is left as paper. Narrow that band and the design gets bolder; widen it and more of the picture is described in marks.

What lino can't hold

This is the part that saves blocks. At your chosen printed size, the tool measures the actual thickness of every line and every gap, and marks anything under the limit.

Red — a line of ink too thin to survive. It will crumble as you cut round it, or break up under the baren.

Amber — a gap of paper too thin to clear. You will not get a gouge in there cleanly, and it will fill with ink.

Circled — a small island of ink standing on its own. These do not fall off a lino block; they are attached to the backing like everything else. What they do is get knocked, crushed under the baren, or lifted when you peel the paper. If you are cutting a jigsaw block, though, they genuinely will come away — that is the one case where an island is a real problem.

Warnings are drawn over the preview only. They are never in what you export or print.

These measurements only apply at one colour, where there is a single block with a definite edge to measure. Above that the controls go quiet, and no warnings appear — which does not mean the design is safe to cut, only that this tool is not the one checking it.

Size is the whole point

A line that is fine at 300mm is dust at 60mm. Nothing in the warnings means anything until printed width is set to the size you actually intend to cut. Change that slider and watch the warnings appear and vanish — that is the tool doing its job.

0.8mm is the default limit, which is about right for standard grey lino with a reasonably sharp V-tool. Softer battleship grey, or a blunt tool, wants more. Japanese vinyl and a sharp knife will hold finer.

Getting it onto the block

• Download PNG — the design as it appears, at working resolution.
• Download mirrored — the same, flipped. This is the one to trace onto the block, so the print comes out the way round you drew it.
• Print at size — the design at true size, tiled across as many A4 sheets as it needs, with crop marks to line them up.

All three follow what is on screen. At one colour that is the black and white block. At two to six it is the flat colour version, which is a proof to look at rather than something to trace — the separate blocks come from Reduction Ladder.

The first printed sheet is a scale check: a 100mm square with instructions. Measure it. Printers routinely scale by a percent or two without telling you, and a 2% error is a 3mm error across an A3 design. If the square is not 100mm, set your printer to 100% or "actual size" and print again.

What it can't do

• Make the artistic decisions. It reduces tone honestly; whether the result is a good print is entirely down to you.
• Bridge islands for you. It can tell you an island is fragile. Where a bridge should run is a drawing decision, and a bridge in the wrong place ruins the image — so it says what it found and leaves the pen to you.
• Separate the colours into blocks. It shows you what a picture reduces to in four colours. Which block carries which colour, in what order, and what ink to mix for each pass is Reduction Ladder's job, not this one's.
• Know your lino. The 0.8mm default is a reasonable average, not a measurement of the sheet on your bench.
• Recover detail that isn't there. A small, soft or noisy photograph gives a mushy design. Start with the best original you have.

Where your data lives

Your settings are saved in this browser. Your picture is not saved at all — it stays in memory for as long as the tab is open and goes when you close it. Nothing is ever uploaded.

Putting it on your phone

Tap Install app and it goes on your home screen with its own icon, opens full screen, and keeps working with no signal. On an iPhone or iPad the button shows you where to find it instead: Safari puts Add to Home Screen behind the Share button.