What are the best open image formats that support layers?

Question

I've commissioned an artist, which all images have been delivered in PSD and PNG formats.

As a Linux user, PSD files don't open well on software like GIMP and ImageMagick due to the issues with clipping masks, plus I'd like to avoid a proprietary format if possible regardless as these will be going on a public project on GitLab.

What are the best image (or project) formats that support layers? It's preferred if it's widely supported, but if it at least works with GIMP and ImageMagick, that'd be good enough since a script will automatically export it to more conventional formats like PNG.

I've tried looking at many standard ones, however they don't support layers. TIFF I learned isn't completely open, which is why even though Photoshop supports layered TIFFs, other programs can't open each layer. EXR doesn't have good support when reviewing what Photoshop exports to when GIMP imports it.

Answer 1

In the realm of graphic design, no such format. TIF is indeed problematic due to its nature and its not just about photoshop extensions but the way extensions are implemented. Not usually a problem in graphic design. In graphic design the real horse is PDF but while pdf may be open to standard its not exactly open and riddled with problems in your usecase.

However there is a format made for VFX work that fits this bill and that is Open EXR. Now Open EXR is not exactly a run of the mill format so it may not suit your needs as it supports things that GIMP does not. The format isnt really intended for end users or clients but for VFX pipeline and asset needs. You can however find that your designer may have a problem with this. Also VFX people has some weird ideas about layers in your usecase.

PS PNG may also have similar adobe convolutions injected to it buyer beware.

Answer 2

Some ideas:

Your requirements "looks" detailed, but they are not detailed enough. Let me explain.

PSD files don't open well on software like GIMP and ImageMagick due to the issues with clipping masks

A clipping mask is a vector shape that contains stuff inside, either another vector shape or a raster image.

In this case, I would say SVG is your best option. But I really doubt you actually need a clipping mask. You probably need a layered mask.

But you probably do not really need a layered mask either. Probably simply the alpha channel will work.

You need to define if you need, for example blending modes. Some blending modes are easier to implement than others, even a browser can handle them.

But things do not look soo good if you need a special filter to be used "on the fly" (not already rendered into a layer), this we probably need a specific file format used on an application. In this case, the original requirements should have been using Gimp in the first place.

I am not sure if Image Magic can open Gimp files. Probably converting from PSD to Gimp will be a good option, flattening some specific layers with PSD only features.

Another option is simply PNG... Remember that Fireworks used PNG as a file format. Yup. Those PNG files had layers, and masks and texts, and whatever strange things inside and they were PNG files. I even asked Greg Roelofs if the file was, and he told me that it was. Of course, you would need to program the features you want and cry when no other program recognizes that feature.

If you only need alpha channels, you probably can implement some kind of 7zip file with simply some PNG files inside. and prepare a script to layer them on your project declaring the blending mode or something. Which sends me back to SVG.

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What I mean, define what specific features you expect with the term "layer".

Answer 3

I've concluded that OpenRaster (ORA) would be best for my use-case.

The format works well between GIMP and Krita, it's also easy to convert it to other formats, and its goal is to be an interchange format. It fulfills the requirements of being an open image format with layers and takes it a step further as it can be opened as a zip archive to view each layer without the need of specialized software.

I am not using EXR due to it not working as expected in testing. Namely, that the file exporting from Photoshop does not look as expected when importing in GIMP.

I'm not using TIFF due to it not working as expected, this is supposedly due to how Adobe extends the spec.

Answer 4

I think you'll find that TIFF has the best balance of wide adoption and compatibility without being an explicitly proprietary format. The fact is that most graphic designers use Adobe software so if other designers will need to access this using a format like Open EXR will likely cause more problems than it will fix. It certainly depends on your intended audience though.