Quick PS brush question

[Ramah]

I was wondering if someone could answer an annoyance I've had for a while when using brushes with PS.

I made a few forest brushes out of multiple tree brushes but when I place these brushes the sharpness of the resulting image can differ immensely. I have every option turned off in the brush dialog, so I have no size jittering, opacity changing, wet edges... nothing. But if I place the brush 10 times I can get 10 different images, ranging from pin sharp to looking like it's had a 1px gaussian on it.
I would have thought, that with all controls of the brush turned off then it would repeat exactly the same every time.

Does anyone know why it doesn't? And more importantly, does anyone know of a way I can make it so that it does?

[Daelin]

It's not a problem specific to PS, I experience it with GIMP as well. It has to do with where you place the brush in relation to the pixels. Look at the attached, for example. The dots are all placed with the same 1x1 smooth brush. It's one of the downsides with raster-based programs like PS and GIMP. Vector-programs, like InkScape don't have this problem, because vectors are infinitely scalable.

[Ascension]

Interesting. It's sort of like putting the dot of the brush between two pixels and the software makes it fit by blurring it. I've never had this problem in PS CS, but I don't use mountain brushes either. I'll have to see if I get similar results on an experiment.

[Midgardsormr]

Try the Pencil tool instead, it doesn't automatically anti-alias the edges.

You were wondering what it was for, weren't you? (-;

[RobA]

Vector-programs, like InkScape don't have this problem, because vectors are infinitely scalable.

Though they will still have this problem if elements are on on pixel boundaries when being exported as a raster (which is how they are normally used).

For Inkscape, there is a nice extension called PixelSnap http://code.google.com/p/pixelsnap/ that will take all the objects and align them to pixel edges to stop them from exporting fuzzy.

-Rob A>

[Ramah]

Try the Pencil tool instead, it doesn't automatically anti-alias the edges.

You were wondering what it was for, weren't you? (-;

This doesn't work. It's crystal sharp yes, but it loses all the mid-range tones of the brush.

So basically, I'm stuck with placing and replacing a brush until I manage to get it smack bang in the correct part of the pixel? :s

There ought to be a Snap to Pixel command or something. Gah.

[Midgardsormr]

I see.

I don't see any options for turning off subpixel accuracy, so I suspect the best solution is to work at a higher resolution.

[Daelin]

Yeah, working at a higher resolution and then scaling the image down gets rid of the problem. Alternately, you could draw one brush that fits your sharpness/blur needs and then copy/paste that, that you give the "snap-to" option. You would have to do this with each of the different brushes, of course.