Expert: LizaL - 6/29/2005

Question
Hello again,
I have taken tiffs of skull bones for study to be labeled.  I first correct the photos in photoshop, save them and open them in Illustrator in order to label them (with a layer for each label for future ease of having one label on the screen at once) then export the file as a JPEG.  The details are important as many students will not be able to ever get to see "real bone" and only see "plastic bone" which lacks importamt textures and holes.  

The destination for these are to be read with a PDF reader such as Adobe Reader and distributed on CD.

Size wise I want them to fit on the screen but be able to "zoom" in to see more detail.  

Thanks so much,
Robert
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Followup To
Question -
Hello and thanks in advance.
I have over 130 high resolution digital pictures that I want to continue to be able to zoom in to see details.  But I want to have them as a smaller file than they are currently without losing too much/any details.  (I will be working them in Illustrator and then saving them as a JPEG to put in PDF formate.)

Currently they are 14.1 M pixal dimensions; width 2560, Hight 1920,document size width 35.556, hight 26.667; resolution 72.

What do I need to adjust to make the file size smaller without getting it to pixalize?  Can it be done to find common ground between file size and detail?

Photoshop 7, Illustrator 10, windows Xp profession 2002.
Thank you.
Answer -
Hi Robert,

I need a little more information -- you say you're working with the photos in Illustrator, and saving them from there. What are you doing with them in Illustrator? Why aren't you saving them in Photoshop?

Another question: What size do you want to reduce them to?

One last question: What is the destination of these pictures? Are you printing them, or using them on the Web?

If you can tell me these things, I can help you much better, but it's hard for me to tell you what to do when I don't know all the info.

So please post back and let me know these things, and I'll try my best to help you.

Unfortnately, JPEG compression uses an algorithm called "lossy" compression, which means you will lose some detail, somewhere, at some point. Usually when saving as a JPEG, the lossy compression will reduce things that the computer sees as redundant, or unnecessary (such as large areas of sky, water, etc.). And of course, the more you save as a JPEG, the more you lose -- it's sort of like making Xerox copies of a copy.

Now, if you're planning to use these pictures on the Web, you can use the Save for Web function in Photoshop, which is found under the File pulldown menu. But this is for optimizing graphics and pictures for use on the internet, so those are the algorithms used when compressing this way.

However, you can give it a try and see what happens, even if you're not using these photos for the Web. Under the File menu, select Save For Web, and then you'll see a dialog box come up. If you see only one image, click on the tab at the top of the screen that says "2-up." Then you'll see the original image on the left, and a copy of it, which is the one you're going to optimize, on the right.

Select JPEG from the little pop-up menu on the far right side of the dialog box, and adjust the settings as you wish to reflect Low, Medium or High quality JPEG, and make sure you check Optimized. You can also manually adjust the quality with the slider underneath the Optimized box.

It's pretty intuitive -- as you can see, you can also make it progressive if you like, as well as add a little blur or a matte color, and you can embed a color profile too.

But those things aren't the big issue here -- the big thing is, look at the bottom of the dialog box. On the left, you'll see the original file size, and on the right, now you should see a size that is greatly reduced.

Take a look at this:
http://little-works.com/all_experts/saveforweb2.png

This file measures 1900x1200 ppi, and the original file size is over 6.5MB -- and using Save for Web, the compressed version is 178K, without changing the physical dimensions.

Now, I don't advise using this as a method for saving your pictures for printing, unless it's for your own personal use; I'd never do this for, say, a freelance job. But you could try printing an optimized version, and see how it turns out.

And in terms of Web display, leaving your files at the huge dimensions they are as originals is a bad idea, too. You have to consider that people who have slow connections, or even dialup, can't and won't take the time to wait for a huge picture to download.


So that said, let's go back to the beginning! If you post back and tell me the additional info I asked about, we can go about resizing your picutres more conventionally! This is, admittedly, a "down and dirty" method!:


Lisa

Answer
Hi again Robert!

That's what I thought you'd say, about Illustrator -- I thought you were doing something with text there.

And thanks for posting back, because this gives me a lot more to go on. But -- you didn't tell me a specific size you're sizing down to! ARGH! Just kidding -- I'll try to think hypothetically.

1. Your original files are TIFFs, which isn't good, in terms of file formats. Saving a JPEG from a TIFF can result in messy resolution, because TIFF saves with lossless compression (good for resolution and page layout programs, but bad for file size), and as mentioned, JPEG saves as lossy (good for file size, but bad for resolution, if saved and re-saved). I'm wondering if you're not losing some quality just by virtue of your saving TIFFs as JPEGs.

That would be one thing I'd think about -- aside from file size -- your quality might be suffering because of this.

2. Your work flow sounds right -- but I'm wondering, where is the large file size coming into play? Are you wanting small Photoshop files, or small Illustrator files, or small PDFs?

You can control the amount of compression in a PDF like this:
http://little-works.com/all_experts/nocompression.png

What I did here, in the Compression area, was just save the file with no compression, which would give me a higher-resolution PDF -- but also a larger PDF, in terms of file size.

3. I also took a picture of a skull I have (I'm sure it's not like what you're working with, but it was all I had, when it comes to bone) -- I did what you're doing, except my original file was a JPEG.

I used Save For Web in Photoshop, then imported the file into Illustrator, added a text tag, then created a PDF. My original image was 35in x 35in, resulting in a file size of 320k when using Save For Web. My PDF was 4.9MB and you can see it here:
http://little-works.com/all_experts/ -- it's the test.pdf file.


You have to be the judge here -- is this resolution enough for you, in terms of viewing the PDF? Because if it is, I would suggest using Save for Web in Photoshop.

I would also, if at all possible, see if you can receive your original files as JPEGs. I realize this might not be possible but it would be better than going from TIFF to JPEG, which I have to think is playing with your resolution.

Anyway, take a look at the PDF and see what you think, and if you don't think that's going to work for you, I'd suggest posting at the following forums. Maybe someone else has a better idea, if mine won't work for you.

1. Photoshop 911 -- general Photoshop issues
http://www.photoshop911.com/

2. Retouch PRO -- this is a photo retouching forum, but these folks deal with sizing issues all the time, and might very possibly be able to handle this issue better than I.
http://www.retouchpro.com/

3. This guy has a lot of info regarding hardware such as digital cameras, but the forums seem to have some pertinent info you might be able to use.
http://www.stevesforums.com/forums/view_forum.php?id=70


Hope this helps, and let me know what happens!

Lisa