[rez]

And when saving the finished tilt work what should one save it to, to minimize loss?

yep, just a greenhorn trying to learn something here.

So after saving the tilt (before crop as crop is JPG Lossless) one can notice a minute loss of detail comparing the before and after of the pretilt and the tilt.

What is the JPG Lossless Rotation option in the menu right above JPG Lossless Crop?

[Snard]

I believe that JPG Lossless Rotate would only be possible for 90 degree increments. (i.e. 90, 180 & 270 degrees)

[JVJ]

What is JPG Lossless, guys?
First time I ever heard of it. Is it a new version of JPEG? What I understand about JPEG is that EVERY time you save a file in that format, EVEN IF IT IS ALREADY IN JPEG FORMAT, it resamples and recompresses the file. Does anyone know if this is no longer the case?

Regarding detail: Whenever you rotate the image, rez, the software is remapping colors to different pixels, so you're right that you will lose some detail (hopefully only a little, at 300 ppi). That's because pixels are only horizontal and vertical, so when you tilt them, they have to realign themselves into a 90 degree grid. A little of the clarity is lost that was originally there as some of the "averaging" is not perfect.

This is one reason why you should try to only rotate an image ONCE. If you don't get it right the first time, it's much nicer for the image if you undo the rotate and try it again from scratch.

[John C]

There's never been anything in the JPEG description to require loss, until you turn on compression, as far as I know.  It wouldn't surprise me if the majority of software handled it poorly, but at its heart, it's a pixelmap, so a 100% quality (zero compression) save should be identical to the original.

Of course, if it's less than 100% quality, any change you make to it is going to cause further degradation, but that's not what you're talking about, I don't think.

[OtherEric]

I believe the 90 degree increments are 'lossless', even with JPEG, since you're already dealing with a grid.  So rotating the image 180 degrees so it's right way up won't hurt you; none of the data needs to be recomputed.  I must agree that, after that, you need to only rotate once.  It's not obvious the first time, generally.  But it doesn't take many tweaks before you start losing huge amounts of detail.  (I found that out the hard way, I really need to go check some of my earliest scans and see what I need to redo because of that particular mistake.)

[Yoc]

Yep, Jim is right about each save being worse with jpgs Rez.
This is why I tend to rotate (ctrl-z to undo if it doesn't look right, never saved and try again)
then I crop and if needed I might 'shift-s' to sharpen once.
FINALLY I save it all just ONCE with 's'.
Because you are saving a jpg as a jpg again there will always be some loss.  Nature of the beast.

When scanning I use TIFF files.  Irfran can work with those the same way as jpgs.  And when I'm all done I save them a final time as a jpg at whatever size I pick.  1500-2000 pixels tall in my norm.

I've no idea how JPG Lossless works Jim, sorry.

Rez if you hit 'F1' while in Irfran you can read the built in manual for pointers.

[JVJ]

I get your point, jcolag, but if JPEG at 100% isn't saving any bits for you, what's the point of it? And I think most people are NOT leaving the 100% setting on, but ARE compressing their files to some degree, which leads to cumulative degradation of the image.

I use TIFF or PSD (generally PSD as my workflow uses the files in InDesign, which can read PSD files - including their layers) always and always save the original scan and work on a copy. Disc space is SO cheap these days that there's very little reason that I can see not maintain your raw scans. Even then, I do all my correcting on adjustment layers and, now with PS3 and PS4, Smart Objects, so even sharpening can be done without changing your raw copy.

When working for the web, I still work as if for print and after the final save I will reduce the file to the size and resolution that I will use on the web, sharpen the results, and then save it as a JPEG (or GIF). I don't bother saving the reduced file as a TIFF or PSD. If I want to make a change to a web image, I find it best to return to the oversized original file, make the change and reduce (and sharpen) again.

It sounds, Yoc, that "Lossless JPEG" works only in rotating in increments of 90 degrees where no pixels need to be averaged, but simply remapped one-for-one to a new grid position.

[John C]

Yep.  I agree completely.  And since JPEG was created, I believe, specifically for transmitting photographs over the network, its silliness is explained in that it's just misapplied technology.

I mean, JPEG makes perfect sense for the web, since one format and one algorithm lets you quickly get muddy pictures and slowly get pristine photographs.  But whoever decided to start using the format for everything has really made everybody's life miserable.

And yes, very few people understand a tenth of this (because they don't need to), and so they never turn off the compression even when they should.

On the other hand, for comics, in the very few pages I've scanned, I've seriously considered increasing the compression.  That's not because I want a smaller file, but rather to iron out the printing inconsistencies.  It's only recent comics, after all, that you could call "continuous color."  Unfortunately, the results don't bear my reasoning out.  Dang reality!

(You've also hit the nail on the head, I think, in that a "real" common image format should be built on layering.  By itself, that would solve an absurd number of problems...but we both know that the next day, everything in the world would be encoded into a single image.  Sigh...)

[JVJ]

ALMOST Free (plus postage) reference material:

Any of you Photoshop users out there want/need some Photoshop books? I am in the process of cleaning out some bookshelves and have the following available for anyone who wants them:

1. Adobe Photoshop 6.0 User Guide
2. Adobe Photoshop 6.0 Classroom in a Book (w/CD) List price $45
3. Adobe Photoshop 6.0 Web Design - List price $40
4. Photoshop 6 Bible - Gold Edition (w/2 CDs) List price $65
5. Adobe Photoshop 7.0 User Guide
6. Photoshop 7 WOW Book (w/CD) List price $50
7. Photoshop 7 Savvy (w/CD) List price $50
8. Adobe Photoshop 7 One-Click WOW! (w/CD) List Price $30
9. Photoshop 7 Down & Dirty Tricks - List price $40
10. Adobe Photoshop CS User Guide

First come, first served. Improve your skills, learn more about your tools, do better scans/edits, and give me some shelf space. Strictly a non-profit deal here, but I hate to just throw these things away.

let me know if you're interested.

Peace, Jim (|:{>

and HAPPY NEW YEAR to everyone at GAC.

[brian]

Hey I have a question (or a poll) for our scanning public. How do you handle horizontal (landscape) rather than the normal vertical pages? I have been mainly dealing with them for ads, but I actually ran into a few issues where the comic pages are ALL horizontal. My normal approach is to limit / count the pixels vertically rather than horizontally, but that actually never made complete sense since the horizontal pixels always matched the number of pixels associated with the screen resolution and applying them vertically would just be an arbitrary reference.

Opinions? What does every one else do? 

[JVJ]

Hey I have a question (or a poll) for our scanning public. How do you handle horizontal (landscape) rather than the normal vertical pages? I have been mainly dealing with them for ads, but I actually ran into a few issues where the comic pages are ALL horizontal. My normal approach is to limit / count the pixels vertically rather than horizontally, but that actually never made complete sense since the horizontal pixels always matched the number of pixels associated with the screen resolution and applying them vertically would just be an arbitrary reference.

Opinions? What does every one else do? 

My inclination would be to maintain the same resolution (300 ppi or whatever) and just rotate the files before compression and assemblage into the cbr. Granted, the landscape format would allow for a higher display resolution but that would mean a larger file.

My 2

[brian]

Which is what I do now. I set the # of pixels top to bottom instead of right to left. It just always seemed odd. LOL

Thanks Jim