[Digital Genesis]

Alright, here are a few examples and observations..
(those with short attention spans can skip to the end)


I've found that scanning at 256 grayscale and 100 dpi (why is everyone so hung up on 96 anyways?) and saving to tiff format gives a good starting base.

I then import the picture in WGOP42 and optimize it for either jpg or gif.


Gif tends to have an edge over jpeg, as far as image integrity goes. A certain loss of color graduation happens, but there are absolutely no artifacts in the finished product.
Gif also produces sharper, more crisp images with a rich black foundation.

Gifs should be saved with 4 bit, 16 colors for best balance between size and quality.

I must have been sleepy last night when I said 3 bit.

Jpeg presses the file size even further down, while still maintaining an acceptable image quality.
Jpeg does best where color graduation can hide the artifacts.

Jpeg 176kb - 24 bit


Jpeg still gives good results with b/w lineart images, but here we must accept 'washed out' blacks and noticeable artifacts however. Compare this crisp gif to a washy jpeg!

(the jpeg does have an advantage in smoothing the small letters and details at this low resolution, due to its high color count.)

Gif 160kb - 4 bit


Jpeg 122kb - 24 bit



Loomis' book is mostly white with black lineart. There are very few (if any?) real grayscale images in it. So GIF would be my choice of format.

Gif 192kb - 4 bit


For jpg of same go to : http://www.geocities.com/mytograf/loomis1.jpg (jpg - 112kb)

( I don't have the book, but I remember from borrowing it at the library when I visited the states. At the time I had just started drawing and didn't realise the importance of his entire work, so I just copied a few pages on a xerox.. .. oh woe is me, regret regret =)


I've kept the file sizes below 200kb and stuck with gif and jpeg to demonstrate. However, if this project is to really sparkle, I suggest using PNG at 8 bit.
File sizes would go to around half a meg each, but the quality would be impeccable.

Personally, I don't mind paying for a bit of bandwidth to get good quality scans of the book. Who cares if the size is 100k or 500k? It's a one time d/l and the book is on the endangered species list.
The only reason I see for not doing it high quality, is if there's a limit on the bandwidth available at Ants In 3D. (but in that case, an account or two at geocities could serve as excellent image depots, instead of having the images on the main server)


To remain sane, regardless of what kind of format is chosen, I suggest the optimizing is done in WebGraphics Optimizer Pro 4.2, or similar program, which allows batch processing.

Summing up:

The scans, for best quality and compromise on size, should be scanned at 100 DPI, 256 Grayscale and saved as GIF, 4 bit format, 16 colors.
JPG should only be used for 'real' grayscale images, as the artifacts are quite annoying in lineart. Unless it's saved at very high quality.

For top notch stuff, PNG, 8 bit, is preferred. (or jpeg at very high quality)

Use a dedicated image optimization program to save lowest sizes possible at desired quality

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[This message has been edited by Digital Genesis (edited February 02, 2001).]

[Anthony]

Thanks man, I'll definately mess with it. I'm trying to keep the image size down because I realize how long it takes a 56k user to get a 500k image...and when there are 200 of them...! But we'll see. I think you're right about gif on the text and line art pages.

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-Anthony
Carpe Carpem

[waylon]

One other thing that will improve your file size IMMENSELY without much loss of quality is to play with the levels a bit before saving the file. Specifically, adjust the upper slider so that the grain of the paper becomes solid white.

I got Digital Genesis' 192k gif down to 88k, and it looks just as good. (still 16 colors)
http://fear.incarnate.net/~vlad/sijun/loomis2.gif

[This message has been edited by waylon (edited February 02, 2001).]

[Anthony]

What program did you use Waylon?

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-Anthony
Carpe Carpem

[waylon]

I used photoshop for the levels, then a program called irfanview to convert it back down to 16 colors, since I've never trusted photoshop's color mode changes.
http://www.irfanview.com/

(It's mainly an image viewer, but I've found it does pretty good dithering when decreasing color depth, so I use it for that too.)

But the changing the levels is the most important thing. A solid color (white) is MUCH easier to compress than paper grain, where every pixel is pretty much different than the one next to it.

[Digital Genesis]

Wow, how could I have missed that one?

Thanks Waylon!