Q&A For Digital Photography Page 2
Finding Image And File Size Information In Photoshop
Q. I use Photoshop 7.0. When I right click on an image it shows the compressed file size, the same as the detail view. What I am always reading is that the file will open to some size that is larger than the file that is stored. I always assumed the JPEG files were in a compressed form. I thought I saw this larger number in Photoshop or Elements once in some forgotten area of the program.
Also, I have often read that the size of the image file determines the size enlargement you can make from it, usually something like, "You need a 12MB file for an 8x10." This is the kind of information that I feel does more to confuse than inform. First, it seems to me that the size of the file would change with the amount of compression in JPEG, etc. Second, isn't the (interpolated?) resolution the factor to look for? Since usually we are told that 300dpi is needed for photo-quality printing would it be better to state it in dpi instead of the file size?
I just purchased a Canon EOS 20D and really can't figure how large a photo I can print. I am hoping for 11x14, and praying for 13x19.
A. I apologize for not being as clear and precise with information
on Photoshop 7.0 and XP, but it has been a long time since I have had that old
version of Photoshop running on my PC, and I doubt if my PC gets turned on more
than once a month.
Anyway, there should be a small triangle in the bottom border of the Photoshop 7.0 application window. If you have an image open, a click will pop up a dialog with a menu that provides access to most information about the image file, including file size and document dimensions.
In Photoshop you can easily get image size information, including dimensions/resolution and uncompressed file size, by going to the main menu bar and clicking on Image, and then on Image Size.
Then, at the top of the Image Size dialog window the file size is indicated as its uncompressed Photoshop file size. And at the top section the image pixel measurements are indicated. In the bottom box the image dimensions and resolution are indicated.
If you uncheck Resample Image by clicking on it at the bottom, and check Constrain Proportions, you can then change the resolution and the image size dimension will also change proportionally. You can print an image with a resolution of 180dpi and obtain good print quality, at 240dpi you will obtain very good quality, and at 280dpi you obtain excellent print quality. Any higher resolution does not improve print quality.
Use the Image Size dialog with one of your Canon EOS 20D files and you will be able to see what sizes you can print without using interpolation to increase the image size. If you use your 20D in JPEG file format do not use resample interpolation to increase the image size. If you want to make 12x18" high-quality prints on 13x19 paper from your 20D, set the camera on raw file output. Use the Canon software to convert the file and output a TIFF file in
16-bit depth. Then open it in Photoshop and use Image Size with Resample on and set the size to 12x18" at 300dpi. Once the size is increased go to Image/Mode and reduce to 8 bit after you have made all color adjustments to the image. Then you can print your big images and get the best quality the camera will produce.
Moving Plug-Ins From An Older Version Of Photoshop To A Newer One
Q. Enjoying and learning a lot from your Digital Darkroom Resource CD (Volume 2). I have SilverFast SE installed (I'm using Windows XP) and it is available when scanning to Photoshop Elements 2.0 (File/Import, etc.). I have updated to Elements 3.0 and would like to use SilverFast there as well. How do I move it to Elements 3.0?
A. There are two ways to get access to SilverFast in your
newly installed Elements 3.0. If you are going to leave your old Elements 2.0
installed, then go to Preferences in Elements 3.0 and under the tab "Plugins
& Scratch Disks" at the top select the file/folder with other plug-ins
(like those in Elements 2.0) providing access in Elements 3.0. That folder should
be on your hard drive under Applications/Adobe Photoshop Elements 2.0/Plugins/.
If you have difficulty finding this file folder, do a search using the search
term SilverFast, then the location should come up.
The other method is to locate the SilverFast plug-in file that is now in 2.0 and move it (drag) to the corresponding folder (Plugins/Import-Export) on your hard drive under Applications/Adobe Photoshop Elements 3.0.
The Old And Difficult Choice Between Quality And Price
Q. Did you evaluate the new Microtek scanner? If you needed a 4x5 scanner now, which would you choose? For me image quality is important and I would like to be able to make prints 20x24" and larger for a show I'm having in a few months. However, value is desirable as well and if I don't need to pay the premium for the Kodak three-line CCD I won't. For larger prints, do you keep your output resolution around 300dpi? I've heard you can go lower because viewing distances should be greater.
A. If quality is the paramount issue the Kodak three-line
CCD of the Microtek ArtixScan 1800f must be the choice. If you have to go to
something less costly I would recommend the Epson Perfection 4990 as the best
performing six-line CCD flat-bed now available for what you have in mind.
For very large prints your image size/resolution can be as low as 180dpi and you'll still obtain good print quality, but if you can get 240dpi that's a better compromise and will provide very good image quality in a 20x24" print.