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Reducing Photos for Posting

Posted By: Lightseeker

Reducing Photos for Posting - 07/14/04 06:24 AM

I just posted some photos of Point Bonita in the Map Room, and I noticed a phenomena I've seen, but not as prominently, in the past. When reducing a digital photo from 2560x1920 to 500x375 pixels for posting, I often get a moire effect, as is especially noticeable in the sky in the shot of the lamp room. I use Paint Shop Pro for managing my digital photos. Does anyone know of a way, using PSP or other software, to prevent this when downsizing? I expect to lose some quality, especially sharpness of detail, when reducing pix, but I'd hope that I could do better than those.

Thanks,

Bruce
Posted By: Lighthouse Joe

Re: Reducing Photos for Posting - 07/14/04 02:02 PM

I didn't see any moire effect in your photos. Are you referring to "jaggies"? It could be from your monitor. Is it a CRT or LCD? I also use PSP. Resize using "Bicubic". Then Unsharpen Mask (USM) with these settings:

Radius: .4 - .75
Strength: 150 - 300
Clipping: 0

Adjust Radius and Strength to your liking (avoid halos).

See if that helps.
Posted By: Lightseeker

Re: Reducing Photos for Posting - 07/14/04 08:14 PM

Thanks, Joe - it helped a LOT!

I've posted some samples in the Play Room. The sky in the first shot has distinct bands of color (actually shades of grey) around the lantern room - at least it does on my LCD monitor. Using Bicubic instead of Smartsize eliminated most of the effect, smoothing out most of the tonal gradations. The unsharp mask smoothed them even more, and also improved the overall sharpness of the photo. I may have overdone the unsharp mask a bit, but just for a test, it worked great! I'll definitely use the Bicubic Resample method of resizing for all future photos, and apply the unsharp mask on a discretionary basis.

Thanks again!

Bruce
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