It has come across my dashboard again, and this time I’m on my comp, so here’s the copy-paste of my last reblog (plus minor additions and clarification):
You don’t need a ruler for straight lines. Your program provides you with tools to do this.
Photoshop: Touch the screen/tablet where you want your line to start, lift pen, hold shift then touch where your line ends (varying results on line variation from thick to thin)–you can even keep holding shift and just keep clicking away. You can use your mouse for consistent line weight. If it’s just horizontal or vertical, then hold shift and draw your line. You can use the pen tool (P) to create a path, right-click, then select ‘stroke path.’ Checking ‘simulate pressure’ will taper your lines–be sure to have the brush size you want selected before stroking the path. Pen tool also lets you create easy curves. The line tool (U, or shift+U to cycle to it–looks like a rectangle in the tool bar–called ‘rectangle tool’) will let you start at point A, then drag to point B.
Image 1: Both examples are set to the same size and tool. For smaller brush sizes, the brush tool has the potential of becoming lost if enough pressure isn’t applied–unless a mouse is used for consistent pressure.
Painter: No line variation: press V then click away–it will create a straight line between each point you click. Vertical, horizontal, and 45° (with variation from pen pressure): hold shift then draw in that direction. Line variation in any direction: use the pen tool (P) to create a path of the lines you want (don’t worry about the ‘shape layer’ this creates, you can delete it later if it bothers you, Painter likes to make extra layers when you’re not looking), go back to your brush (B) then select ‘align to path’ option from the toolbar, great for making curves, too–or perspective if you’re drawing in perspective (you’ll want to have set up your grid beforehand for this to work nicely).
Image 2: These tools allow you apply varied lines along paths you have laid out or along a perspective grid you have set up.
As you can see, even though the programs are different, they have similarities. If I remember correctly, GIMP should be similar to Photoshop’s setup (with different hotkeys, of course–that was an eternal battle for me). Most programs are going to follow either creating a path/vector line, or drawing in conjunction with the shift key. But you can always look up ‘[art program] straight lines (or whatever function)’ when you become lost.
If you still have issues, the easiest and most reliable way to get your angled straight line would be to create it on the horizontal or vertical path (usually just some combo of shift and drawing) then rotate/transform it. Even if you have to rotate a horizontal/vertical line, at least you’re not fighting blind ruler placement and still having to correct your line via rotation/placement.
Also, you never know what potential damage the ruler may cause to your pen nib or tablet.
As limited as some programs are, they’re more powerful than you think. Different programs have different perks. I like Photoshop’s transform tool better than Painter’s since it’s all right there and right-click accessible and it has ‘warp.’ I think Painter has better default brushes and sensitivity to pressure.
As for tracing, I would either just scan or take a photo (no matter how crummy the photo), bring it into the program, then trace/clean up. Better results, no chance of slipping.
The best thing you can do for yourself is learn the program(s) you’re working with.
