Photoshop
- When creating a new file, make sure the pixels per inch are 300
- To convert an image from RGB to CMYK, go Image-> Mode-> CMYK
- You can work in RGB so there are more options on photoshop then save as CMYK
- Here is an example of the same green in RGB then in CMYK, there is a dramatic shift in colour
- Example image (photos are RGB images): Click view, gamut warning to get a grey overlay which obscures the colours that aren't printable. You can make adjustments with this overlay on.
- One way to edit these colours to make them printable is to alter the hue and saturation.
- Another way is to go image -> adjustments -> replace colour. (This is a good way to just change the part of the image that needs changing instead of the whole image)
- Go view, proof colours. This means you are still working in RGB, but you see the duller colours, which are what gets printed.
- On the colour picker there is an add to swatches button. You can also go to the colour library, and see the pantone colours. If you have a reference number, just type this, and the colour you need will come up.
- Unprintable colours have a warning triangle
- To make an image duotone, make it greyscale first, then go image -> mode -> duotone. For monotone, replace the black ink with a spot colour. Click the box with a diagonal line in next to the colour box, and you can alter the duotone curve.
- If the line of the curve is diagonal, the new ink is like-for-like as the old one, for example, 50% black is now 50% blue. Here I have altered both curves:
- Save the file as a .psd and you can open it in Indesign, and the colours will be loaded to the indesign palette.
- A channel is a black and white image that stores information about where each colour is placed.
- You can save cut out selections of an image in the channel palette (channel menu-> new spot channel) then edit the colours of this selection. The spot colours are printed over the other colours. You can use any of the photoshop tools to alter the selection channel, such as using the paintbrush or eraser to neaten up the selection.
- If you wanted a spot varnish on your print, you would select the area you want to be varnish, and make it a spot colour, and colour it in with a colour that you have not used on the image, then you would tell the printer that this certain colour is the area which is to be varnished
