re-sizing ?

[GregO]

Photoshop Question: If I need to have an image sized to exactly 1in x 1in at 1000 resolution, what is the best way to accomplish this?

The out-of-the-camera image is 4752 x 3168.

Thanks!
GregO

[srwatters]

The first thing I would do is to crop the image to square format BEFORE resizing. Once you have the composition you want, save an intermediate copy in a lossless format (like tif). From there you can then downsize to 1000x1000 pixels. Depending on the content of the image, you can choose the appropriate algorithm. If there are many sharp edges and you want to preserve them, I might try the bicubic sharper algorithm. If it's a portrait, then perhaps straight bicubic would be better. If you don't want sharpening, then consider bicubic smoother. Compare the master with your smaller version and go from there.

[GregO]

Thanks for the reply! I can work it out now with your info.

Thanks again,
GregO

[MicWayWal]

Why wouldn't you use the crop tool, set to 1 inch x 1 inch @ 1000 resolution? Wouldn't this do everything Scott said but do it in one step?

[srwatters]

It would, but what if he didn't like the resizing algorithm? Why redo the crop operation two or three times. Once I like a crop, I hate trying to recreate it because I never seem to get it the same again. Plus it's always nice to have a master for each ratio I create. Disk space is cheap...

[MicWayWal]

What do you mean "if I don't like the resizing algorithm"?

I have been cropping like that since PS 2.5 and I have never had a problem.

[srwatters]

You are aware that there are several different resizing algorithms employed by PS, right? In the preferences panel you can choose which one is used by default by tools other than image->resize. That means when you implicitly resize, you cannot choose the algorithm. I'll give you a prime example where this is critical. I typically use bicubic sharper as my default algorithm, but if I have an image where moire issues arise due to patterned clothing, I will use straight bicubic or sometimes even bicubic smoother to avoid the issue. If more sharpening is required in the downsized image, I can selectively sharpen using Nik Pro Sharpener.

Relying on a single algorithm for down (or up) sizing your images may result in less than optimal results. Of course I'm OCD and have the luxury of spending more time on individual files since photography isn't a business for me. YMMV.

[MicWayWal]

Thanks Scott,

Yes I knew that PS had different algorithms. I had run tests 7 or 8 years ago with the different preferences in CS1. I could not see any difference in the prints that I made. They were 16x20 and portrait images. So I have never changed it from the default of straight Bicubic. This was after the second generation of cameras that came out that stopped most of the moire problems we had with the first generations of digital cameras.

I also thought you had something checked that would allow you to view the changes on the fly instead of going back to the preferences panel again and again.

[srwatters]

For portraits, straight bicubic is probably fine although I prefer bicubic sharper when downsizing large files since you can lose some sharpness going from 39MP to 525x700 for web images. I shoot with a medium format camera that has no anti-aliasing filter, so even at 39MP moire can sometimes be an issue. And even if there is no moire present in the source image, sometimes the downsizing will cause it to show up. The worst is ribbed tank tops and other fine regular patterned fabrics.

If you use the crop tool for interpolation, there is no choice on the fly for selecting the resizing algorithm. At least I don't see it in the CS4 toolbar. I know you can choose with regular image->resize.

[skyoftexas]

Thanks for the insight.

Michael