'blend add' - Support Alpha i/o PNG in Photoshop

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Photoshop has not allowed users to successfully leverage the PNG format to the degree RTVFX artists utilize pre-multiplied alpha blending (aka : ‘blend add’)

we have had to use SuperPNG to do this (git location)

it is a long standing issue that Photoshop cannot grant this flexibility during save/open — i.e. they are not entirely sure how/why it is an issue

is it your pipeline that force you to use PNG? there’s a lot of different formats to chose from, .tga for example

anyway, I usually work in a .psd file and just export the .png, I never open the .png, only overwrite it

companies/teams make decisions, many of us just are in the churn… :slight_smile: pipeline


my guess PNG use is a legacy from RGBA4444 used in web games that has permeated mobile… (which fwiw you needed to use Fireworks & PNGquant to get 4444 format and compress it as small as possible since photoshop didn’t have the toolset)

it manages project file size for version control; keeps those dozens of gigabytes of textures for 3D assets far more reasonable.

PSD format is still reserved for art teams; but a large file format version control for Source is separated from project

in the meantime we use superPNG, which, frankly, illustrates the need for alpha flexibility native to the tool

… and let’s not forget awesome new animated png format for full 8888 animation we’d like as well -
APNG - Wikipedia

As the post states
photoshop saves PNGs with transparency rather than separate Alpha

At alpha 0 rgb data is destroyed by ceiling it pure white.

Even when not using Blend Add, Photoshop’s PNG handling causes problems with bilinear interpolation on transparent edges. Almost every project I’ve ever worked on I’ve pushed to default to using TGA for all exported content, or require installation and use of SuperPNG otherwise. So many times I’d walk over to a coworker’s desk when they have some sort of export issue and almost 100% of the time it would be caused by using the default PNG save.

For my personal stuff I usually stick to using the source PSD with an explicit alpha channel. Unity recently made a change that causes PSD files with transparency to fade to solid white … :face_with_symbols_over_mouth: As best I can tell this is the default behavior of the official PSD reader, but I have no idea why Unity changed it as it’s literally never the wanted behavior for real time stuff.

Really, it’s not wanted ever. This is also how 3ds Max opens PSD files with layer transparency.

Random bit of history here, but at one point Adobe changed TGA saves to have the same open behavior as PNG has, in that the alpha was opened as layer transparency instead of a separate alpha, which also clears any RGB values in those areas. I believe it was version 7.0 released in 2003, as they very quickly released 7.0.1 and issued a patch (unusual for the time) with that change reverted. There may have been a lot of backlash from that change.

it ‘annoys me’ that a specific engineer at adobe is vocal ---- suggesting we we are hacks with a bias… the industry as a whole is biased? :exploding_head:

  • ceiling RGB to white,
  • destroying alpha channel
  • ‘quick export’ performing auto-trim

how is that^ not bias , or some knee-jerk low-level principles??

baffling as it is the opposite of elevating/growing and facilitating the graphics world – Adobe : help us help you stay relevant

That’s a community forum you’re linking to, and none of those people responding are Adobe employees. That ACP badge is effectively “this is someone who uses adobe products and active on the forums” and not much else. Even the STAFF badge is likely just those who work on the forum itself. Most large companies have official rules that say actual employees working on a product are not allowed to use those sites.

Most Adobe users are likely going to be doing stuff for web or otherwise working within the Adobe product “sphere” (in which case stuff like Illustrator and Premier actually handles PSD transparency nicely). For those uses cases everything works as expected. It’s kind of the wrong place to make a scene about it. Honestly we’d have a better chance of calling them out on twitter, Adobe is just going to ignore the support forums.

However Photoshop has mostly ignored the 3D community. Even the addition of the “paint on 3d objects” stuff was added with the premise that it would help graphic designers, not 3d professionals. I’ve seen some legit official Adobe responses in the past to these kinds of requests which were met with “But how will this help web people? We don’t care about 3d.” The fact Photoshop is the industry standard for this already and there aren’t any really good alternatives has also reduced much interest on their part in trying to make anything better.

I tried to use that photoshop family support forum a bit lousy…not to mention signal-to-noise ratio :frowning: