Reduce png image from 24 bit to 8 bit, but maintain good colour?

StormyStudio

Good evening,

I'm just producing a range of backgrounds for my game, they don't need any alpha/transparency.

So after creating them in photoshop, as 24bit images, I've tried to use 'save for web' and save them as 8 bit images. the file size difference is great going from 270kb to 40kb, but the image/colours are paler. Obviously this is due to the fewer colours in the range.

How are people getting round this?

design219

Make sure your original images are in sRGB instead of AdobeRGB. Other than seeing possible "grain" (due to the 256 color limit) the saturation should be very close to 24 bit, just not as smooth.

missm

Pale images? Mine get a little brighter, but have you tried to change the presets in photoshop? bellow png8 selection you can try with "restricitive, adaptative, perceptual, web ...

synthesis

I have seen some reduction in quality using 8 bit...but not enough to be dissatisfied. Make sure you check out the quality on the actual iphone device...things look different there than on a cpu monitor...much sharper and brighter.

Also...try boosting the image levels or the color range to get brighter images.

JGary321

I use 8bit & personally didn't notice any difference when using photoshop. Maybe the difference is so minor. but It definitely does not detract from anything imo.

synthesis

You do get a little more pixelization in 8 bit. I noticed it in high contrast spots...such as vivid white glow effects on royal blue backgrounds. But the file size reduction is worth the tradeoff. Not enough quality reduction to cry to mommy about.

StormyStudio

Thanks for the replies, I will try the sRGB mention.

The images aren't currently ruined, they just get brighter/paler/slightly dessaturated.

Admittedly you don't really notice once it is in GameSalad.

It was just very noticeable in photoshop, going from some bright 'Mario World' style colours to a less bright happy place. I tried the varying settings in 'save for web' but it had no real effect.

By the way it's not a mario game, that was just a reference to the style.

JamesZeppelin

when going 8 I get spots around the edges of the transparent parts. I never really played with the setting after seeing them.

Ill give it a try thanks

JGary321

Yea, going 8 is not recommended with images with transparency. There is a way to do it, but it involves Adobe Fireworks also. Not worth my time personally.

I go 8 on all BG's & 24 on everything else basically. But honestly it has saved me several MB's. I went from each BG being anywhere from 200-300 down to anywhere from 25-75 on average. So it definitely is a big difference maker.