[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]

Re: [APML] Picture Resolution For Web



Hi Eddie:
I'm coming into this question late and you probably have more than enough answers by now (hopefully all pointing to the same thing) but anyway:
Don't set the *resolution* of your images for the web! The resolution of the standard monitor display is the best any viewer can see, so any resolution you set will be modified, probably at several levels. What you want to do (and I found this out from  very good advice from someone) is set the final *size* of your image in pixels. PC monitors are set for 72 pixels/inch, so if your image is sized to 720 pixels wide, it will display on viewers' screens as 10 inches wide, a very comfortable size for most. I usually set mine for 700, 750, or 800 pixels wide depending on the height.
 
I finish up my images in PS at high resolution and save as psd or tif for archival purposes. Then, for the webpage, I change the size to the 700 to 800 pixels width mentioned above and ignore all the other size variables on the PS Image / Size dialog. Then I select save as jpeg and look at the estimate that PS provides at the bottom saying what the download time will be at 28K. I then reduce the jpeg quality slider until the download time is below 20 or 25 sec. Then hit OK and you will have a jpeg that will display on the great majority of monitors at 9 or 10 inches wide and will look quite reasonable.
 
Bert
 
Bert Katzung
katzung1@attbi.com
www.astronomy-images.com
----- Original Message -----
To: APML
Sent: Friday, October 25, 2002 12:49 PM
Subject: [APML] Picture Resolution For Web

Hi All
 
I think this may have been covered in the past, but I can't find much on it.
 
What (and I'm sure you'll all have different answers) is the "recommended" resolution for astro pictures to display on the www.
 
I'm using PS6 and have final film images approx 56MB (16 bit) at about 3800x2550 and final ccd images approx 4MB and 1300x850
 
The reason for asking is that I can display a ccd image at, say, 1000x???, and image looks fine (using the medium option for quality under "saving images for the web"in PS when converting to JPEG) and file size is around 100Kb, but if I do that with a film image (reduce size to 1000x???), converting to JPEG produces a file size of over 200Kb.
 
Should files  which are the same size (1000x???) be the same size (100Kb)?? or am i doing something wrong.
 
If I reduce some film pictures (especially wide field), to 1000x??? and reduce the file size to about 100Kb (using the low quality option) the image looks like it's set in jelly!!
 
Help and/or advice appreciated
 
Thanks
 
Eddie Guscott