I've seen a lot on converting jpegs to .BUM's but not the other way 'round. I seem to be stuck with a bunch of six year old texture maps, and I can't use .BUM files anymore, of course. I tried just changing the file extension. This worked for one of my graphics viewers, but not Poser, or Photoshop. Ack!!!

Strange, because changing the file extension worked for me ??? You also have to change the extension(s)in the pz2 file of course. Or otherwise there is the "simplified method of making your own bump map" : 1 -> load the texture (with changed extension) in a picture editor. 2 -> make it black & white. 3 -> enhance the contrast (more black/white, less grey). 4 -> save as a jpg under another name. Step 3 is not an absolute necessity, this method works for making trans maps too. I don't know any but maybe there is also some utility doing the conversion for you if your "bunch" is too much to change manually.

Try changing the extension to .BMP instead, then convert to a .jpg

Ah! Changing it to .bmp , then converting it to a jpeg works fine. Thanks! Gordon

You're welcome :-)

Some image viewers look at the file header instead of going by the extention to determine the file type. Poser obviously ain't that sophisticated :-)

A word of warning, if I may, starting with some boring technical background. All versions of Poser from ProPack onwards can use any greyscale image as a bump map, where white denotes sticking out bits, and black is dented in bits. A good bump map is not just a desaturated version of the texture map - although that can form part of it - but a separate image which has been specially prepared to give the required effect. Poser 4 uses a proprietary image format (.BUM) which is based on BMP, but with information only in the red and green channels. I surmise this was done to make rendering faster, along the lines of the old .RSR geometry files. When Poser 4 is given a greyscale image as described above, it converts it into the .BUM format (and the Windows version of P4 does the conversion wrong, but that's another story). The .BUM format isn't just a simple translation; as the others have said, you can change a BUM file's extension to .BMP and read the file in any image viewer, but if you do that you'll readily see that it bears no relationship to the original image file. There was some discussion a while back on converting (or should that be reverting) .BUM files to greyscale images, but I can't find it now, and can't remember if a solution was found. But one thing is sure - although the methods described above will give you results, they won't be what the artist intended. Thanks for reading. Or, if you bailed out of my techno-rant halfway through, :P

Can anyone find that re-conversion thread again? I've recently discovered a few oldie-but-goodie props sitting in my runtime from my Poser 4 days, which only have .bum files so unless I forget about using the bump maps, which I don't want to, I'm kind of stuck. These are very nice old props, and I'd like to be able to use them again properly.

You can use .BUM files in P5 & P6 if you plug them into the "Gradient Bump" node instead of the "Bump".

I know, but I use DAZ|Studio which would have the same "not quite right" bump effect noted upthread. What I'm looking for is some fairly straightforward way to split, fix, and re-merge the RGB channels to recreate the original greyscale bumpmap. I have PaintShopPro, so the splitting and re-merging is easy enough. I just need to know what's involved in the middle step.

Well, the rename it to a .bmp, convert it to greyscale, and store it as a .jpeg approach worked okay for the one render I was doing, but that texture was relatively low res. I'm not sure there's a good way to get a one-to-one conversion. P4 .BUM maps use that embossed look, and P5 & 6 use the greyscale approach, which probably gives a more realistic look. I think that almost any approach is going to be more of an approximation that a direct translation. If I were doing it again on a higher res texture, I'd probably tinker a lot more with the contrast of the greyscale image before using it for a final render.