Instantly colourising greyscale images (kind of):

We're reprinting a book at the moment, one from years ago, back when we used to use OPI (low-res image substitutes) and DAT2 tapes for backups (ew). All's well and good, we dusted off the DAT drive and went to restore the files to the server, only to find that tape 2 had snapped. The tape with all the high-res colour images on it. So, we're left with just the OPI low-res files, and greyscale high-res images, used for the student's workbook and the teacher's manual. There's no WAY was I gonna scan that many images in (it'd take too long, and if you scan from an old book it's pretty crap quality anyway), so I fluted around and came up with a handier way of doing it:

1. Open the greyscale high-res image, and convert to RGB (or CMYK) mode.
2. Open the low-res colour image.
3. Resize the low-res image to 300 dpi, making sure it's the exact same pixel dimensions as the greyscale version. It looks really crappy, 'cos it was originally only 35 dpi.
4. Copy and paste the low-res file onto the greyscale version.
5. Change the layer blending mode of the pasted layer to Colour, et voila, the image has instantly been colourised. High-res, full colour, every bit as sharp as the original high-res.

Not exactly an all-purpose procedure, useful in everyday life, but it'll come in handy if I ever have a low-res colour version and a high-res greyscale version of the same file. Which happens... never, but hey, I thought it was cool.

Printing large images:

If you're working on a large file, it can take aaaaages to print. Imagine working (as I do) on an A4, CMYK, 300 dpi image with dozens of layers. It can take ages for such a large file to print.Instead of waiting, I set up an action to speed it up. Just record yourself doing the following, and the image will print in a fraction of the time:

1. Image>Duplicate. In the option box, turn on "Duplicate Merged Layers Only". This means that the duplicated image will be flattened - only 1 layer to print.
2. Image>Image Size. Set the resolution to 150 dpi. A printout at 150 dpi isn't much differentthan a printout at 300 dpi, so it's handy for proofing purposes.
3. Obviously, you'd print the final image at 300 dpi, but if it's just to check how something will print, or if it's to show an editor, 150 is fine.
4. Print the image.
5. Close the duplicate document without saving.

Simple as that. All I have to do now is hit F12, and it'll run through all that in a matter of seconds, and the printer will print the image in a fraction of the time.