Tiff-support?

[ehofmeister]

This may have come up earlier, but I couldn't find any info on it, so here goes..

Why can't you save renderings in tiff-format?

Which of the supported save-formats delivers the best quality?

How compressed are the JPG and PNG formats?

[dalomar_cg]

Re: Tiff-support?

Tiffs are a pretty old format. In fact tiffs are very much a "pandoras box" in the sense that they can almost be like a plug and play module in terms of compression or color format, or range (8 bit, 16 bit, 32 bit). As far as why we don't write them, I don't really know, but considering the lack of requests it wouldn't seam like we are missing too much.

Here's some more information on the formats we do support...JPEGs everyone is familar with, and basically have two parameter when saving information to that format; smoothing (which almost no one uses) and compression. We don't allow control of either (this will change in the future), which leads to images that generally have too much compression. I generally try to stay away from jpegs (kinda hard though), but in this case I do not recommend saving your images from vfr as jpegs

Bmps are straight forward and have no compression and no other goodies, its an antiquated format, but it gets the job done and everything can read them.

PNGs are my personal favorite. The have lossless compression so you're data won't be trashed, we support saving alpha information, and they can be read by absolutely everything. To me, its my everyday format for quick saves of images that are just tests or quick visuals. The only thing at the moment is that if you have the alpha channel available in the vfb, then your png will always be saved with an alpha. Hopefully we will give the option to save with or without it later, but thats how it is for the moment.

TGA (pronounced targa) are another good one on my list, specifically because of the way they handle the alpha channel. Its just much easier to deal with in photoshop, so thats why I like it. Other than that its an all around good format with out any loss of information. The big downfall is that besides a real image editing program (PS, corel) or video/compositing software (premiere, AE, combustion), you're not going to have any luck reading them. I don't know why that is, but I still like em. I think you could use targas in place of tiffs fairly easily.

HDRs and EXRs are really the "hardcore" format, and are probably going to be what you'll want to use. If not right away, then try to phase yourself into. The reason is simply information. HDRs and EXRs are a float point format, meaning that they can handle color data that is brighter than white. This is really important for Image Base Lighting, so thats why most of the images used for environment mappings are HDRs. The advantage that this has for a rendered image is that you can change exposure in a much more effective manner, since the whole range of color values are stored within the image. The colors are more accurate as well, which prevents huge gaps in the histogram like you'll get with 8 bit images. The thing to keep in mind with these formats is they are set up for proper linear workflow, which means you'll have to to pay attention to the gamma value when editing them. Also, the ability to edit these images as 32 bit images (ie with their full information) is relatively limited. There are options out there, but you'll have to go out and grab another app (hdr shop specifically). PS CS3 is better, but definitely not where it needs to be. For all of these reasons, I think Targas might be a good way to start out. Not that HDRS or EXRs are hard to deal with, it just takes a few more steps to work with them effectively.

Hope that helps explain a few more of the options that are available.

[Micha_cg]

Re: Tiff-support?

... and Xniew is only software I know to disable the alpha channel of the PNG. Or do somebody know a way per Photoshop?

[dalomar_cg]

Re: Tiff-support?

There probably is a way through photoshop, but I don't explicitly know it. PNGs don't separate the alpha channel which is the only issue I have with them (and why I love targas so much).

I believe that through David's Image Scripting Tools I should be able to remove the alpha channel. I just haven't gotten around to it, so I'll get it written tomorrow (or tonite maybe). Either way, you're going to have to download the plugin file so you can do that now if you'd like.

[esef]

Re: Tiff-support?

thanks for sharing all the info above.