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Old Oct 28, 2005, 7:48 AM   #1
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what would you say would be the most precise noiseless
exacting, fastidious, perfected by experience method to raise in Pshop CS2
in the image size dialog box using BICUBIC smoother,
a 17.2 MB jpeg fine file to lets say 25 MB,30MB or even higher to still
be able to obtain a decent image. Given these files are of excellent
contrast focus and of great quality to begin with.
might i begin:
constrain proportions and resample image are both checked
scales styles ( yes or no ?)
bicubic smoother.
do i increase the width or height by a certain percentage?
do i need to increase it by 10 or 20 or 30 % then save
and repeat?
is it a one shot raise and thats it?
please in detail enlighted me
i do appreciate this greatly
gl
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Old Oct 28, 2005, 11:17 AM   #2
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Most people upsample for a reason. It isn't common to say "golly, I think I'll just make that 17.2Mb image 30Mb". Your end purpose for the upsample determines how you resize. I see no reason for an upsample of an image that large except for a large print.

If you are printing you have to crop the image to the right proportions for the print size before messing with the Image Size box. It is possible to do everything with the crop tool, but I would recommend not doing a resample with the crop tool.

I'm guessing you have a 6Mp camera. The largest 11 X 14 cropped from the image will net you around 190 PPI, which is around where I don't resample. But assume you want to resample: Select the crop tool and put 14 inches in the width and 11 inches in the height (or the other way round). Put NOTHING in the Resolution box. Crop the image so the proportions are right and then go to the image size box. With the resample and constrain proportions boxes checked you can just put the resolution you want in the resolution box and OK.

If you are printing smaller than 11 X 14 and not cropping a lot off the image you probably wouldn't want to resample. I haven't seen a photo printer yet that you can see any difference over 250 PPI. Some people swear by larger numbers like 300 PPI and even 340, but they don't share my experience. But if you are going to resample you might as well put 300PPI as the resolution.

The Scale Styles box is immaterial unless you have layer styles like masks or embossing going. Even then I would think you would want those things enlarged with the image. I just leave mine checked.

For an upsample of a large image Bicubic Smoother is usually recommended. The stepped interpolation (SI) where you increase in increments of 2% or 5% is done with straight Bicubic. The easiest way to do that is to make an action if you want to try it. Do an upsample both ways and see if you can see any difference. The SI upsample appears a little sharper, but the stepped increase just introduces artifacts that give the impression of sharpness.

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Old Nov 7, 2005, 5:02 AM   #3
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Hm... I always "only" did a "smart" or "bicubic" resize. BUT I always make sure to choose an "easy" resize - size 2x2, 3x3, 4x4 etc. of original. Never had any real problems with it. After blowing up I make sure to set the image to the correct dpi BEFORE printing (not X*Y at 72dpi or 96dpi but set dpi according to print size A4 or else).

The bad thing is that most deconvolution progs can't handle these big files for some sharpening so you are stuck with "normal" sharpening/levels afterwards.

HTH,
Th.
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