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Old 03-03-2006, 02:10 PM   #1
marlene
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Default Dealing with diminutive digital images

I've got a digital photo that's about 5.5" wide. I need to use it about 8.5" wide on a magazine cover. Ouch.

How do I determine the best course of action -- upsample to keep it 300 dpi, or just enlarge it and let the resolution drop to 195 dpi?

It will be offset printed. I normally insist on 300 dpi, although I don't always get it, but I don't think I've ever run a cover image at less than 230 dpi, if that.

(This is one of the images that has the chromatic aberration discussed in another thread, but the client is going to live with it.)

If upsampling is what I need to do, what's the best way? I'm using Photoshop 7, out of force of habit, but also have PS CS2 installed. If there's a plug-in that works better than whatever's in PS CS2, I'd consider it.

Or is PSP better for upsampling?

And if I upsample, should I avoid sharpening? Will that make it look worse? What's the best tool to use for sharpening?

FWIW, after I do whatever I do (which has to be done in the next couple of days), we are going to get an Epson proof from the local service bureau, so if it looks horrible (either because of the size/resolution issue or the chromatic aberration) my client might opt not to use it after all.

mxh
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Old 03-03-2006, 02:39 PM   #2
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Quote:
marlene: I've got a digital photo that's about 5.5" wide. I need to use it about 8.5" wide on a magazine cover. Ouch.
Sounds painful but what's the pixel count?


>>How do I determine the best course of action -- upsample to keep it 300 dpi, or just enlarge it and let the resolution drop to 195 dpi?

I'm still using Photoshop 7 too...how does it look when you resize up at 300dpi--given my monitor res (1152x864), I know that if I zoom to 33%, I see what I will see when I print. (This is really easy to do if you've never done it...basically, you turn on rulers in Photoshop and then zoom to say 100% and hold up a ruler to the screen and start adjusting the zoom level (down) until the screen ruler and the physical ruler match.)


>>but I don't think I've ever run a cover image at less than 230 dpi, if that.

Sooo...does it look better at 230dpi than at 300???


>>If upsampling is what I need to do, what's the best way? I'm using Photoshop 7, out of force of habit, but also have PS CS2 installed. If there's a plug-in that works better than whatever's in PS CS2, I'd consider it.

I *think* CS2 has more options for upsampling but I don't know for sure since my CS2 is still deskware...'-}}


>>And if I upsample, should I avoid sharpening? Will that make it look worse? What's the best tool to use for sharpening?

Do a Unsharp Mask AFTER you resize. Again, I do my USM at 33% zoom so I can see whether the USM does anything useful (or bad). Try playing with ther Radius setting on the USM--I usually have Radius set to 1.2 - 1.5 but I've found that sometimes bumping it up to 3 - 5 can be useful but also play with the Threshold setting too...


>>FWIW, after I do whatever I do (which has to be done in the next couple of days), we are going to get an Epson proof from the local service bureau,

Do you know which Epson printer (and what proofing paper) they will be using?

Do keep me posted...

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Old 03-03-2006, 03:21 PM   #3
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Marlene, here's a free action action that I use with Photoshop 7.

Works very well for me. http://www.interpolatethis.com/actions.html

   
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Old 03-03-2006, 05:43 PM   #4
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If the target line screen is 150, you really don't need to get above 225 ppi. The rule of thumb has always been 300 ppi, but as best I can tell roughly 1.5 x line screen is all that is really necessary. Even that is a bit high. I think the number should be 1.415926..... [sqrt(2)].

I just got back a 4c postcard that went out with a 144 ppi (because that is what I use for proof PDFs) image because the person I sent the proof pdf to didn't tell me she was done proofing and didn't ask for a hi-rez file. It is a bit soft, but not horrible.
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Old 03-03-2006, 10:57 PM   #5
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The printer asks for 400 dpi. I never asked why. <g> But I always give him 300 dpi and he doesn't squawk.

I suppose I ought to ask him what line screen he's using. But it seems like the rest of the world is happy with 300 dpi, and that's the best I ever get in digital photos, so it's probably a moot point.

I'd be happy if the current image were 225, but I'd have to upsample to get that.

mxh
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Old 03-03-2006, 11:05 PM   #6
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Pixel count is 1662 x 2078.

I can't trust what I see on the monitor. I rely on the color proof. I don't know exactly which Epson printer the service bureau uses, but it replaced their Iris, so it's a high-end model.

I always do USM after resizing and adjusting images, but I always zoom up to 100% -- I don't trust what I see at a smaller size -- to make sure I'm not oversharpening. Sometimes an image looks great at 50% after USM, but when I check it at 100%, I can see the tell-tale white edges of oversharpening.

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Old 03-03-2006, 11:07 PM   #7
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Thanks, Mick! The price is right, so I'll certainly try it out.

mxh
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Old 03-03-2006, 11:56 PM   #8
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Quote:
Originally Posted by marlene
If upsampling is what I need to do, what's the best way? I'm using Photoshop 7, out of force of habit, but also have PS CS2 installed. If there's a plug-in that works better than whatever's in PS CS2, I'd consider it.

Or is PSP better for upsampling?
I'd try both, but above all also vary the sampling algorithms - results may vary depending on image content. Irfanview has another algorithm available which some say is superior to what the "big ones" have to offer. No single technique is best for all images!

Quote:
Originally Posted by marlene
And if I upsample, should I avoid sharpening? Will that make it look worse? What's the best tool to use for sharpening?
Rather than avoid sharpening, you may actually need it after upsampling - dependent on image content. Sharpening should always be the last step, though you might try some gentle sharpening before the upsampling step and compare results (including possible sharpening after upsampling).

Sharpening is a bit of a science in itself... some tools offer shortcuts, but when you want to do it really well, it becomes a technique rather than a tool. Then again, you may not need to go so far if it's goin to be rasterized for print. USM (Unsharp masking) is available in both PS and PSP and is a good general-purpose tool (with different uses); both also have high-pass sharpening (dependent on version - PSP X certainly does). I've also read about PS "smart" sharpening which is another thnig to try. Each of these ready-made tools offer settings you need to play for best results.

Some links about sharpening:

   
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Old 03-04-2006, 12:03 PM   #9
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I don't have PSP, but I'll fiddle with the photo in PS CS2. I'll check out that "smart" sharpening feature.

I do have Irfanview, might try that too.

Thanks for the links, I'll check them out.

mxh
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Old 03-04-2006, 02:25 PM   #10
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Quote:
marlene: I can't trust what I see on the monitor.
Surely you can at least rely on your screen view (at an appropriate zoom level as I mentioned) to at least see if the image is pixelated due to upsizing?

If you hardware calibrated your screen and if the sb will tell you what profile they are using you should be able to soft proof on your screen with a reasonable degree of accuracy...


>>I rely on the color proof. I don't know exactly which Epson printer the service bureau uses, but it replaced their Iris, so it's a high-end model.

If you have a chance to ask them, I'm curious. I'm sure they replaced their Iris many moons ago...I'd bet it's either the Epson 4000 (maybe the 4800) or the 7800 (24" wide vs. 17" on the 4000/4800).


>>I always do USM after resizing and adjusting images, but I always zoom up to 100% -- I don't trust what I see at a smaller size -- to make sure I'm not oversharpening. Sometimes an image looks great at 50% after USM, but when I check it at 100%, I can see the tell-tale white edges of oversharpening.

If you know what zoom level corresponds to print size, then you'd be able to see the USM effects more accurately...100% zoom is not reality...

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