LESSON 05 · DIGITAL FOUNDATIONS

On paper the surface is decided for you the moment you pick up the sheet. Digitally you have to decide it yourself, before the first mark: how many pixels, which colour space, which file format. Get those three right at the start and everything downstream works; get them wrong and you find out weeks later when the picture prints blurry.

SOFTWARE

Finish first: L1, L2, L3, L4

• Photoshop and ArtRage 6 both installed and opening
• A folder on your computer where your artwork will live
• One finished drawing on paper you would like to redraw digitally

WATCH

PHLEARN — Covers PSD vs JPG/PNG/TIFF, saving layered work vs exporting - exactly L5's 'From Paper to Pixels' content, on a current Photoshop build. The 2011 Ctrl+Paint original shows a 15-year-old UI.

THE LESSON

A digital image is a grid of coloured squares. That grid has a width and a height in pixels, and that is the whole truth of the file. Everything else — inches, centimetres, PPI — is a note attached to the file saying how big those pixels should be printed. Changing the PPI number alone does not add a single pixel of detail.

PPI matters at exactly one moment: printing. At 300 pixels per inch, printed dots are small enough that your eye reads a smooth image, so 300 PPI is the standard for anything going on paper. That is where A4 at 2480 x 3508 pixels comes from: 8.27 inches x 300, by 11.7 inches x 300. If a picture is only ever going to be looked at on a screen, PPI is irrelevant and the pixel dimensions are all you need to think about.

In Photoshop this is File > New, and you type the pixel dimensions directly. Check the units say Pixels before you type. To check or change an existing canvas, use Image > Image Size.

Making an image smaller is nearly free; making it bigger is not. Scaling down throws away pixels you had. Scaling up invents pixels that were never there, and invented pixels look soft and mushy no matter which method you use. So the rule is: start at or above the largest size you might ever need.

Sensible starting points. Screen-only work, such as a piece for a school project or something you want to post: 2000 to 3000 pixels on the long edge. Anything you might want printed: build it at print size and 300 PPI from the beginning — A4 at 2480 x 3508, A5 at 1748 x 2480. Your display is 1920 x 1080, so a 2480-pixel-wide canvas is bigger than your screen. That is normal. You will be working zoomed out most of the time, which is a good habit anyway.

There is a ceiling, though: every extra pixel costs memory and makes brushes feel sluggish, so 'just make it enormous' is not a strategy.

A colour in a file is stored as three numbers. The colour space is the rulebook that says what actual colour those numbers mean. Hand the same numbers to two different rulebooks and you get two visibly different colours — this is why an image sometimes looks vivid in one program and washed out in another.

Two rulebooks matter to you. sRGB is the narrow, universal one: it is what web browsers, phones and most screens assume. Adobe RGB is wider — it can describe more saturated greens and cyans — and it is used in print work. Your Artist 12 can show 99% of sRGB and 97% of Adobe RGB, with a Delta E under 1.2, so you own a screen that can be trusted in either.

Work in sRGB unless you have a specific reason not to. Almost everything you make will be looked at on a screen, and sRGB is the space that survives the journey to somebody else's phone unchanged. If you ever do need to change the space of an existing file in Photoshop, that is Edit > Convert to Profile, which converts the colours to keep them looking the same, rather than Edit > Assign Profile, which just swaps the rulebook and shifts every colour in the image.

Split every format you meet into two piles. Working files hold everything you need to keep editing: .psd in Photoshop and .ptg in ArtRage both store your layers, so opening one puts you back exactly where you stopped. A .ptg goes further: it records how much paint is on the canvas and how wet it is, which is what lets ArtRage's oils behave like oils after you reopen the file.

Delivery files are flat. A .png is lossless, keeps transparency, and is the right choice for line art, flat colour and anything with text. A .jpg throws away detail to make the file small, and a bit more every time you resave it — fine for the version you send someone, terrible as a place to keep working. ArtRage exports raster images via File > Export As Image in JPEG, PSD, BMP, TIFF, GIF and PNG.

That PSD option is the bridge between your two programs. ArtRage both imports and exports PSD while keeping layers, blend modes and groups — so a painting can start in ArtRage, move to Photoshop for the parts Photoshop is better at, and come back, without collapsing into a single flat image.

The ArtRage manual puts it plainly: 'Always use Save to save your paintings, don't be tempted to use Export as if it was Save.' Export makes a copy in a flat format for other people to look at. Save preserves the thing you are actually building. Export a .png, close the program, and everything that made the file editable is gone.

So: save the working file constantly, and export only when you want to show someone. Give both the same base name, and keep versions rather than overwriting — dragon_v01.psd, dragon_v02.psd, dragon_v03.psd. Version files cost almost nothing and are the only reliable way back when a change ruins a drawing. One folder per project, exports in a subfolder called 'export'. Do it now, while you own three files, not in a year when you own three hundred.

PRACTICE · 30 MIN

1. Create a folder called Artwork, and inside it one folder per project. Inside your first project folder, add a subfolder called export.
2. In Photoshop, File > New: create a screen canvas at 3000 x 2000 px, sRGB. Save it as project01_v01.psd.
3. File > New again: create a print canvas at A4, 2480 x 3508 px, 300 PPI, sRGB. Save it as project01_print_v01.psd.
4. Open Image > Image Size on the print file. Change only the PPI number to 72 and watch the pixel dimensions stay the same. Then undo it — this is the test that proves PPI on its own is only a note.
5. In ArtRage, create a painting the same size as your screen canvas and make a few oil strokes on it. Save it as a .ptg.
6. From ArtRage, use File > Export As Image to export a PNG into your export folder, then reopen the .ptg and confirm your paint is still wet and editable.
7. Take the paper drawing you chose and decide, in writing, which of the three canvases you would redraw it on and why.
8. Save a copy of the screen canvas as project01_v02.psd so you have started versioning before you have anything to lose.

Done when: You have a folder structure with an export subfolder, three saved working files with version numbers, one exported PNG, and a written sentence explaining your resolution choice for the paper drawing.

Download these and work along with the lesson.

CHECK YOURSELF

Answer out loud first, then open each one to compare.