Raddar opened this issue on Nov 24, 2002 ยท 10 posts
Raddar posted Sun, 24 November 2002 at 12:45 AM
Can anyone tell me how to take an image that is 2000x3000 and reduce it to 800x700, maybe even a bit smaller, without loosing the quality of the image. Every time I try to shrink it I get a much less sharp result. Thanks for any help.
dreamer101 posted Sun, 24 November 2002 at 11:20 AM
I'm not sure if you meant 800 x 700 or 700 x 800 as in the first dimension the width is 2/3 the height. If you keep the proportions constrained you can get:
eg.
467 x 700
533 x 800
700 x 1050
800 x 1200
If you don't keep the proportions constrained, you will have a seriously distorted image.
Any time you increase or decrease the image size it will blur. You can use Filter - Sharpen - Unsharp Mask. In the Unsharp Mask window you will have to play around with the settings. Most of my images I use:
Amount: 50-75%
Radius: .9
Threshold: 1
kruzr posted Sun, 24 November 2002 at 1:19 PM
Hi Radder, The best way I've found to reduce an image, & retain as much detail as possible, is to decrease the image size by 100 pixels, in the Width or Height window, for each reduction, (progressively), until you've reached the final size you want. It takes a little longer than entering the final pixel size in one reduction, but the ultimate image is much better. In the "Image Size" window make sure you have "Constrain Proportions" & "Resample Image" checked, & select "Bicubic" next to "Resample Image". Once you've reached the image size you want, you can then use one of the "Sharpen" filters if you think you need it. This will also work in enlarging an image, to a limited degree. Good luck & have a good one . . . Mark.
kruzr posted Sun, 24 November 2002 at 1:24 PM
My suggestion is for PhotoShop version 5.5, I don't know if the "Image Size" window layout in newer versions is the same or not? Haven't upgraded to a newer version yet.
PunkClown posted Sun, 24 November 2002 at 1:28 PM
Radder, try converting to LAB before resizing any image as well, then just use the Lightness channel, resize the image. The colour channels will remap to the resized lightness channel. You can then revert back to RGB or whatever colour space you prefer using. This (I've been told) can deliver sharper results when resizing. It is also a recommended method when applying the unsharp mask filter, at least according to a Adobe employee who ran the last Adobe seminar I attended. :-)>
kruzr posted Sun, 24 November 2002 at 8:10 PM
Thanks for that little tidbit PunkClown, I'll have to give your, "LAB" Lightness Channel method a try . . . Mark.
Raddar posted Mon, 25 November 2002 at 12:22 PM
Thanks for all the great suggestions. I played around with them all and found they all work pretty well. I also got great results by mixing them all up a bit. Again thanks to you all for the tips.
tasquah posted Sat, 07 December 2002 at 1:42 PM
Radder : I am interested in knowing some more about your resizing tip. I dont want to sound dumb but are you saying i convert ( Image>mode>Lab color ( 8 or 16 bits ?)) then i go channels and highlight the lightness option and at this point its were i do my resizing at ??
PunkClown posted Mon, 09 December 2002 at 9:08 PM
tasquah, the lab reduction (and also unsharp mask technique) was something I saw at a Adobe seminar...you have understood the steps correctly. Now, as for 8 or 16 bits...well to be honest, I never worried about that side of it, I just let photoshop do it's thing with my image and convert the modes. I'm pretty sure it doesn't bring up a dialogue box asking you to choose, at least mine hasn't! I do know that some functions, such as certain filters will not work with certain bit-depths...but the things that don't work in certain modes are just "ghosted out" in the menus to the best of my recollection... :-)>
tasquah posted Mon, 09 December 2002 at 9:58 PM
Thanks for shareing with us what you learned there . Heck i didnt even notice the LAB option before and would never have played with it.