Im posting this in Resources, although its not a pattern, a brush or a gradient.

On my mission to understand how to make a bevel without a script, some people suggested bumpmapping and one thing i was always curious about is what different variations in the bumpmapping process actually do.

I made two experiments. They both show some interesting results, imo.

Here i used a bump map of medium grey on a transparent background, which is blurred more with each step.


In the second experiment i used different color variation for my bumpmap, but blurred them all the same.
It doesnt work with a black blurred map on transparent BG

Good charts, they make it easier to understand how bump mapping works when visualized.

Thank you Esper.
I have experimented a lot with maps before, either bumping or displacing images, before I came up with these tutorials
All those charts are in my head since then.

Thanks for the Charts Esper as mentioned above it is good to have a visual guide.

now that the scientists of Gimp Labs have found out that bumpmapping with white text on a black BG gives the best result (and inverting the colors just inverts the "bevelled" edge), here is a new updated chart for all your bumpmapping needs:

Hello Esper,

I really like all your "Gimp Labs Science", they are very informative and seeing the results in this way allows to better understand their uses.
Thank you.

Bump mapping is basically just the same as emboss except it merges the emboss result to the lower layer automatically.

esper: this is useful, thanks for sharing. but i want to object to your wording here: "best" depends entirely on what effect you're after at the moment, doesn't it?

Steeno: thats exactly what i was hoping for, thank you very much !

it appears to me, it gives the best contrast
if you want less, why not change the depth or the ambient ?

any suggestions how the wording could be changed for the better ?
what does grey do, that black doesnt ?

well, it's easier for me to change the effect by changing the colour than by changing some other parameter, at least in this case. i think maybe it would be better to say what you just said - white on black gives the best contrast.

i agree about the contrast, but then again, how do you know what kind of grey to choose for what you want to achieve ?

esper: hex code #888888, also known as "neutral grey" is my standard .

well yes, but what does that achieve in comparison to white on black ??

another chart, this time bumpmapped with a depth of 20 and combined with the depth 10 chart

esper: to be honest, i can't be sure exactly what, because i havent researched it thoroughly yet. what i know is that neutral grey on white gives a softer contrast than white on black (my guess is about similar to white on black with a depth of 2), so that's why i use it. instead of bumping with white on black and lowering depth with the slider, i bump with grey and get that soft look i'm after at once.
if i was to research it i think there are a lot of factors i would research, like:
1. exactly what depth on a white on black bump map would neutral #888888 on white correspond to?
2. would neutral grey on black give exactly the same effect?
3. would the value of the colour/colours i'm bumping make a difference?
i am a bit curious about all that, but i'm not curious enough to go through all the work of researching it.