Handling Transparency

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Greg the Yeti
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Re: Handling Transparency

Postby Greg the Yeti » Wed 24 Jun, 2015 10:47 am

A "final note" about the Wicked Step-Mother "Anti-Aliasing" (should that be Wicked Aunty?)

It is my feeling that "Anti-Aliasing" is a useful thing to use, but I think it's use is best confined to a single use in the chain of the preparation of graphics. More use of it than this will lead to progressive degradation of the quality of the image.

What I am doing for best quality in "Orphal Conversions" is as follows:-

1) Scan at the highest "native" resolution of the scanner. In my case only 600 dpi. Many scanners quote a higher resolution, which they achieve by "interpolation". Don't bother with it! Files that are TOO big AND lacking in quality!!
2) I save in a bitmap file type. Currently I'm using tif (because some cameras and scanners default to that I got used to using it...) DON'T, DON'T, DON'T save in a compromised file type such as jpg!!!
3) Any colour corrections, to allow for the fact that my current "rubbish" scanner tends to give rather "Washed Out" images, at this stage. I don't save these to the file, in case I want to come back and re-do something.
4) Resample down to a size that is usable in Orphalese. I'm generally going for 25% or sometimes with very large cards down to 20%. THIS is the only stage at which "Auntie-Aliasing" SHOULD be used! It results in a better, less "Jaggy" and smoother, better looking result. See if you agree with me...
5) all other operations. Cropping. Any small Deletions of irrelevant detail etc.
6) Exporting the final images in an appropriate file type.
a) For anything other than FULL Photographic quality images (very rare in Decks!) GIF file type seems to work VERY well. OK it's 256 colours only, but your computer screen does not show all the colours in 32 bit so why bother with the wasted space? GIF files also "optimise" those 256 colours, so that only colours actually used in the image are occupying one of those 256 tones! See for yourself. Most cards on Orphalese at a given size of image are better in GIF than in either JPG or PNG!
b) In that VERY rare case of full photographic quality images, plus you have a monitor capable of doing that justice - like my Iiyama - then experiment with PNG (large files) or JPG (smaller files but often quite bad quality!)

So, a final reminder.

Use "Auntie-Aliasing" for the Resampling Stage, but DON'T use it at any other time!
You will probably find that your software defaults to using it. So you're going to have to switch it off - for most of the time.

This proceedure works for me. See if you agree...
Greg the Yeti


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