Cleaning up hand-drawn images for riso printing

A quick, yet important note on printing hand-drawn images with risograph. Even if the drawing looks nice and clean in RGB, it is (apparently) NOT enough simply to scan and print. Because…

Pixels.

rose-card-dirty

This lovely grey haze around the edges, yes. Invisible if you zoom in on the RGB image on the screen and very visible, when riso printed. Zoomed in, it looks like this:

rose-pixels-dirty

However, good news is that there is a rather simple (and meditative) way to get rid of them. Assuming the image is originally saved in RGB, open it in Photoshop (I have CS2, but I think these functions are still in the same place in the new versions), choose ‘Image’ -> ‘Mode’ -> ‘Greyscale’. Say ‘yes’ to discard colour information and voilá, now the image is in greyscale. Then go back to ‘Image’, choose ‘Mode’ and ‘Bitmap’ to convert it to black and white only. When saving the image, you’ll be asked about the type of coverage you prefer. In this case I used ‘Halftone screen’, but from image cleaning point of view, it does not matter which one you choose. Now, with the image in bitmap, zoom in to 300%, choose a good eraser size (I switched between 4-12px) and get to cleaning. It gives about the same level of satisfaction as cleaning dirty windows, so it’s a great meditative task for anxious days. After the pesky extra pixels are all cleaned up, I’d recommend to switch to brush about same size or smaller (2-5px) and fill in the white gaps on the black areas. When this is done, you’re done and can either save the image in bitmap or convert it back to greyscale.

rose card clean.jpg

And the text looks now like this:

rose-pixels-clean

There you go.

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