PNG vs JPG

**aridzone** · 22 December 2006, 07:25 PM

I've noticed some comments in the forum about using PNG files when
using clipview. Is there a reason for this? I've tried both and the JPG
files are much smaller and quality about the same. Is there something that
I'm missing?

**Egg Bramhill** · 23 December 2006, 02:51 AM

arid,

I'm never sure about this myself but I must admit a preference to using png's.

It is my belief (and I stand to being corrected) that a jpg is a "lossy" file type whereas a png is a "lossless" file type. Therefore if your working with images within Xara it makes sense to use the Lossless png over the Lossy jpg.

**Wizzard** · 23 December 2006, 09:40 AM

Yes egg is right PNG is lossless as is GIF but an equivalent PNG can be compressed more than its GIf counter part, also PNG is a patent-free image type.

**gwpriester** · 23 December 2006, 12:57 PM

Are we talking about 8-bit PNG or True Color or True Color + Alpha PNG?

8 Bit PNG files, like GIF, use a select palette of no more than 256 colors. I have found that for the web, an 8-bit PNG bitmap, with a limited palette of colors will look cleaner and sharper than a JPEG file with 20% compression (80 on the slider setting).

JPEG images are fine for photographs. But they do not do well with areas of flat color, especially red. Even small areas of red bleed.

If you are preparing a high resolution (300-600dpi or more) document for high quality printing, then JPEG with about 10% compressioin (90 on the slider) or a True Color PNG, or a TIFF are best.

So the short answer is there is no short answer

It depends on how you intend to use the image.

Gary

**Egg Bramhill** · 24 December 2006, 03:44 AM

Thanks Gary.

**aridzone** · 24 December 2006, 06:59 PM

Thanks guys

I know that every time you save a JPG file you loose quality.
But if you try to avoid this it seems to work well with pictures.
It's also true JPG doesn't work well with flat colors.
And if you want to use transparency then PNG or TIFF is the only way.

**Wizzard** · 25 December 2006, 09:23 AM

true but there is no transparency for tiff's in Xara yet and to get the best from png it needs to be true colour with alpha transparency.

**learned** · 26 December 2006, 05:22 AM

Originally Posted by Wizzard

true but there is no transparency for tiff's in Xara yet and to get the best from png it needs to be true colour with alpha transparency.

When we talk about alpha transparency here, does that mean I should be able to open the png in photoshop and see a true alpha channel (i/e b&w mask)? I'm totally new to Xara and fairly new to PS. I love the little bit I've played with Xara, but for the gaming I'm doing I need to be able to end up with a TGA with a B/W alpha mask to indicate in game transparency.

**molucca** · 26 December 2006, 05:44 AM

I Photoshop, you would load a selection from the layer transparency. Then save the selection to see the alpha channel. This may depend on the application your using, as some see things differently.

Rich

**learned** · 26 December 2006, 05:58 AM

Originally Posted by molucca

I Photoshop, you would load a selection from the layer transparency. Then save the selection to see the alpha channel. This may depend on the application your using, as some see things differently.

Rich

Sweet! I just tried it with a quick single color circle, did the layer transparency and created an alpha. Saved as a TGA and it imported perfect into Second Life. Building just got a LOT more fun! Not quite as nice as going direct from Xara, but pretty dang close.