PNG White Halo (Photoshop)

[Guy]

Right. (And that border around his head in the last pic shows that the original mask was not 100% transparent there)
Is that how you've been doing it for yours, Yogoda?

Alphasoldier, it would seem that this method is both quicker (simply fill black and then save with that option set) and better (maintains 100% transparency rather than 99%, though admittedly this is a negligible difference). This is what I was trying to say in my first post except I didn't realise programs generally default to white on 100% transparent pixels – Yogoda now points out that it's an easy setting to change.

I would guess that the reason programs default to white is purely for the sake of compression. A detailed background that is entirely invisible simply makes the image larger for no real reason.

[Lady-Succubus]

Your method is quicker assuming the program allows you to set the color of transparent pixels. Otherwise, it's impossible without having to bring the image into another program, which is a bit of a hassle.

[Moogie]

It does indeed sound like the process is much simpler in GIMP compared to Photoshop. Perhaps CS4 handles this better.


@Sindhi: Feel absolutely free to use them in any way you like. I didn't spend much time on them, so if you want to make any edits or tidy him up a bit, that's also welcome.

[Alphasoldier]

It's not the fact that GIMP handles it better, it's the fact that the default on GIMP is that it has an alpha channel instead of integrated transparency.
I bet that, somewhere deep hidden in Photoshop (perhaps less deep in CS4), it has the option to create and save the alpha channel instead of transparency in the picture.
None the less, as said by someone before, white pixels take less space than complicated colors on places where you won't even see them so it's logical it defaults on that.

[Guy]

Hm, I searched around and confirmed that Photoshop does not have a setting like GIMP does (which seems odd, given that Photoshop is by far the biggest and most bloated image editing program in existence). If you're having to remove halos a lot, it may well be worth your time to download GIMP or some other program that can do this. I'm sure drawing black lines around your images gets tedious after a while

Alphasoldier, I'm still a little fuzzy about what you mean when you talk about alpha channel vs transparency but it sounds like you're referring to the way the program presents the image to you and allows you to work with it, rather than something to do with the PNG format itself or how the program actually saves it. The setting in GIMP that Yogoda mentioned is simply a checkbox that you get when saving the image (Save color values from transparent pixels) – I would be surprised if it actually treats PNGs any differently to Photoshop in the manner that you're talking about.

[Lady-Succubus]

What Alphasoldier means is that there is no alpha channel in Photoshop: instead the alpha channel is represented by simple "lack of color data" in the actual picture. Therefore, where the image appears to be transparent in the channel is where the alpha channel--and the white color-- is defined to be. If I'm understanding him correctly.

And as his post below states, I was not. ._.

[Alphasoldier]

As the tutorial given comes from SecondLife, which also has such Halo problem it's because it always converts the image there, either resizing it or changing the format it also treats the completely transparent pixels as white ones, eventually, when resizing it to it's default sizes (always to the power of 2), it mixes pixels again.

And all I said Guy is that instead of using a transparency layer, they simply just put transparency into the editing. And that any pixel that's transparent is defaulted to white so it costs less memory, that saving color values from transparent pixels is something Photoshop should have too, thought sadly does not.

Anything else you might've said has really not come through to me as you're confusing ME now, I thought I was quite clear earlier on.

[Guy]

Great, so we confused each other . I think I understand what you mean now, although what I was saying was that I think you'll find GIMP and most other image editing programs treat transparency just the same as Photoshop does (my program Acorn doesn't have any features for working with channels at all). The only difference in GIMP is the presence of that checkbox

[Sindhi]

Thanks, Moogie, we would love to use your Li in our mod!

I find going back and forth among Gimp, Photoshop 7,  and My Paint seems to get the job done; the only problem I have is remembering to save My Paint files as png transparent the first time I save there; if I forget that part I have to cut the object out of the background again and sometimes have the white halo problem. There is more than one way to cut the background, thankfully, and I am learning which way works best for which graphic. I'm still mostly using the mouse and My Paint, but need to get more confident with the stylus and wacom pad. When Yogoda goes home I will have the desktop again, which is more comfy for using the pad. I still don't understand why sometimes I have a white halo problem and sometimes I don't. You guys have probably already explained it but I am not understanding. It's ok, I am used to having a steep learning curve...

[aerozol]

It's ok, I've read it all a few times and don't really get it either!
I kind of understand, but I think a problem may be that default eraser on photoshop doesn't leave a halo, while the edge of a brush often does. Or the other way round. But still not sure.

If Derek lurks here perhaps he could let us know what he uses (:
I'm using Photoshop, which probably isn't the best sketching software anyway. I may just download something else, since it doesn't look like there's an easy solution.

[Guy]

As Alphasoldier briefly explained earlier, when an image gets scaled/stretched/rotated/distorted or otherwise manipulated to anything other than its natural form, a type of anti-aliasing is needed to keep smooth edges and maintain the clarity/detail of the image. When Aquaria does this, it can result in pixels around the outline of the image being blended with pure white pixels in the fully transparent portion of the image. The solution is simply to make the pixels in the transparent portion black instead of white, but Photoshop doesn't make this easy for you.

This isn't to do with the tools you use to edit the image, it's just that Photoshop doesn't save the colour of fully transparent pixels and instead records them as white. It does this in the interest of saving file size (it considers PNG to be a "web format") - solid colours compress easily in the PNG format while high detail that is invisible (see the Li head in my earlier post) is mostly pointless and doesn't compress well. A smarter thing for it to do would be to set the colour of the fully transparent pixels to the currently selected background colour, but I guess Photoshop isn't concerned about this

In the end though, I'm pretty sure the whole problem shouldn't actually be happening and is probably a fault of the image-manipulation code used by Aquaria (SDL?). I wonder if it would be possible to fix it when Aquaria goes open-source...

[Alec]

White halos are photoshop's fault.

[frostyfrog]

Another solution could be (I think) use Paint.Net to resize/scale and turn off anti aliasing. Then you could select the inner pixels and blur them a tiny bit if you wanted to.

[Lady-Succubus]

White halos are photoshop's fault.

That makes me wonder... did the devs use photoshop? XD

[aerozol]

White halos are photoshop's fault.

Hm yeah that's what I gathered. And unfixable on there too huh, no plugins or anything, based off my googling.
I guess I'll download something else in a bit