Colour settings and ICC profiles in Paint by Zaweba

A photo that looks perfect on your monitor and dull on a phone usually has a colour management problem rather than an editing one. The fix is to know which colour space each image lives in and to carry that information with the file. Paint by Zaweba handles this through Edit > Colour Settings, opened with Ctrl+Shift+K, plus Assign Profile and Convert to Profile for individual documents.

None of it is complicated once you see what each part does, and most people only need to set it up once.

The Colour Settings dialog

Colour Settings is where you choose your working spaces: one for RGB, one for CMYK and one for grey. These are the spaces new documents use and the spaces Paint by Zaweba converts into when a policy asks it to. You also choose the rendering intent, which decides how colours that don't fit the destination get squeezed in, and whether to use black point compensation, which keeps the darkest shadows mapped to the darkest black the destination can show.

The profile policy says what happens when a file arrives with a different profile from your working space, or with none at all. Settle that policy before a batch of files from a client arrives. Respecting a file's embedded profile is the habit most photographers prefer, because it honours what the camera or the sender intended.

Profiles to choose from

Built-in profiles include sRGB, Compatible RGB, Wide RGB, Grey 2.2, Display P3, Rec. 2020 and linear sRGB, and every profile installed in Windows is listed too. So if a print shop sends you their ICC file and you install it, it appears in the same lists.

sRGB is the safe space for anything that will be seen on the web or on most screens. Display P3 is wider and matches many modern phones and laptops. Wide RGB and Rec. 2020 give more room for heavy editing, particularly in 16-bit. Linear sRGB is useful for compositing and lighting work where maths on light values should behave physically.

Assign versus Convert

These two commands sound alike and do opposite things. Assign Profile changes the label on the file without touching the pixel numbers, so the colours on screen shift. Use it when a file has the wrong profile or none, and you know what it should have been.

Convert to Profile changes the pixel numbers so the colours look the same in a new space. Use it when you need the image in a different space, for example converting a wide gamut master to sRGB for the web.

A quick way to remember: if the picture looks wrong, assign; if the picture looks right and the destination is different, convert.

Exporting with the profile

Exports from Paint by Zaweba embed the profile, so the viewer at the other end can show the colours as you saw them. That is why a wide gamut file still looks correct in a colour managed browser. For the widest compatibility, convert web images to sRGB before export, since some older viewers ignore profiles altogether and assume sRGB.

Common mistakes

Editing in a wide space and exporting to the web without converting is the most frequent one. The second is assigning when you meant to convert, which leaves an image looking oversaturated or flat. The third is ignoring the policy setting and letting every file be silently converted, which can upset a client's carefully prepared CMYK.

Set your working spaces once, leave embedded profiles alone unless you have a reason, and convert deliberately at the export stage. Paint by Zaweba keeps all of this on your own PC with no account or online service, so the colour decisions stay yours.