To re-size or not re-size

[JoshD]

I am curious as how to go about resizing some of my images for prints. Or if I should not resize them at all.

For example, if I want a 12x18 print am I better off resizing the picture to 1620x1080 and then ordering the print? Or should I not resize and let it automatically compress to 12x18? Which is generally the better way to go about it?

I know for 8x10's there is a crop factor involved as well. For 12x18's there generally isn't though from what I have experienced.

Thanks

[freygr]

Changing the DPI of the image does not effect the image just the size of the image in inches or centimeters. As a general rule you send the native cameras image without resizing after doing white balance or color corrections and cropping the image so the printer will not have to guess what parts of the image to crop out if you native camera format does not match the print size ( example 35mm format printing to 5 by 7 or 8 by 10 print). Never reduce the pixel count of you image (cropping does not count). Resize only if the printer tells you to reduce to a set DPI.

Note, on a 12 by 18 inch print: at the low end 1800 by 2700 pixels @ 150 DPI, normal resolution is 3600 by 5400 pixels (20meg sensor) at 300 DPI.

[JoshD]

Changing the DPI of the image does not effect the image just the size of the image in inches or centimeters. As a general rule you send the native cameras image without resizing after doing white balance or color corrections and cropping the image so the printer will not have to guess what parts of the image to crop out if you native camera format does not match the print size ( example 35mm format printing to 5 by 7 or 8 by 10 print). Never reduce the pixel count of you image (cropping does not count). Resize only if the printer tells you to reduce to a set DPI.

Note, on a 12 by 18 inch print: at the low end 1800 by 2700 pixels @ 150 DPI, normal resolution is 3600 by 5400 pixels (20meg sensor) at 300 DPI.

Good information, Thanks.

Question though, when I do the exact same edits on 2 versions and reduce one of the versions size but not the other the reduced size comes out much crisper and cleaner looking. Should I ignore that and know that the "un-sized" photo will turn out fine?

[OldClicker]

Good information, Thanks.

Question though, when I do the exact same edits on 2 versions and reduce one of the versions size but not the other the reduced size comes out much crisper and cleaner looking. Should I ignore that and know that the "un-sized" photo will turn out fine?

I would guess that whatever software you are using to resize is doing some sharpening as well. - Terry

[JoshD]

I would guess that whatever software you are using to resize is doing some sharpening as well. - Terry

Hmm Im not sure. I brought the file in twice. For both versions all I did was "auto" sharpen/contrast. Then with one version I resized it. That was it.

This is in PS Elements.

Strange

**EDIT** I figured out what the problem was. On the one I didn't resize, I didn't even crop it. As soon as I cropped it (even just a tiny bit) the sharpness and clearness came through. Looks fantastic now.

Rookie mistake. Live and learn.

[freygr]

Hmm Im not sure. I brought the file in twice. For both versions all I did was "auto" sharpen/contrast. Then with one version I resized it. That was it.

This is in PS Elements.

Strange

**EDIT** I figured out what the problem was. On the one I didn't resize, I didn't even crop it. As soon as I cropped it (even just a tiny bit) the sharpness and clearness came through. Looks fantastic now.

Rookie mistake. Live and learn.

Note if you resize smaller it will look sharper, but you also lose detail, Also you can over sharpen the image so be careful. You should also be using non-lossy file format during editing (not JPG!).

[Anbesol]

I do resize, to reduce when possible the size of the file being spooled to the printer and to simply trim excess. It isn't necessary, then its also not necessary to send an image exceeding ~ 300 DPI (I typically stick with 240). But I always crop to the aspect ratio. With resizing CS5's bicubic sharper algorithm has been good to my printing needs. I don't usually need to resample when printing larger prints though, only 3.5x5 and 5x7, sometimes 8x10 depending on the crop.

[OldClicker]

Note if you resize smaller it will look sharper, but you also lose detail, Also you can over sharpen the image so be careful. You should also be using non-lossy file format during editing (not JPG!).

I always have to sharpen more when resizing smaller. - Terry

[freygr]

I always have to sharpen more when resizing smaller. - Terry

This is totally depended on the user's software.

[Medley]

This is totally depended on the user's software.

I agree, but respectfully, only to a point. Sharpening contains a physical element- the size of the sharpening halo, which is normally controlled by the "radius" setting.

Reducing an image's size invokes an algorithm that removes pixels from the image, and alters the values of adjacent pixels to compensate for the loss. Software is very much a determining factor in how this is done.

But without exception (that I am aware of) reducing an image also reduces the width of the sharpening halos. Sometimes, that isn't a bad thing. If you're reducing an image to reduce the resolution, but print at the same size, then you would WANT to reduce the width of the sharpening halos proportionally. But if you're changing the image's size in order to print it at a certain dimension, then one should be cognizant that downscaling the image will reduce the size of the sharpening halos, and upscaling the image will increase the size of the sharpening halos.

There are a couple of different ways to compensate for that. The software could do it with an auto-sharpen feature. That's something of a cookie-cutter approach, but it's OK if your changing the size of several images by the same amount. My preferred method is to resize before doing ANY sharpening, and then resize only to match the native resolution of the printer, or some harmonic thereof. That allows me the most creative control of the sharpening process, and ensures that the printer doesn't distort what I've done.

JMO, and I freely admit to being retentive about my sharpening.

- Joe U.

[freygr]

I agree, but respectfully, only to a point. Sharpening contains a physical element- the size of the sharpening halo, which is normally controlled by the "radius" setting.

Reducing an image's size invokes an algorithm that removes pixels from the image, and alters the values of adjacent pixels to compensate for the loss. Software is very much a determining factor in how this is done.

But without exception (that I am aware of) reducing an image also reduces the width of the sharpening halos. Sometimes, that isn't a bad thing. If you're reducing an image to reduce the resolution, but print at the same size, then you would WANT to reduce the width of the sharpening halos proportionally. But if you're changing the image's size in order to print it at a certain dimension, then one should be cognizant that downscaling the image will reduce the size of the sharpening halos, and upscaling the image will increase the size of the sharpening halos.

There are a couple of different ways to compensate for that. The software could do it with an auto-sharpen feature. That's something of a cookie-cutter approach, but it's OK if your changing the size of several images by the same amount. My preferred method is to resize before doing ANY sharpening, and then resize only to match the native resolution of the printer, or some harmonic thereof. That allows me the most creative control of the sharpening process, and ensures that the printer doesn't distort what I've done.

JMO, and I freely admit to being retentive about my sharpening.

- Joe U.

It must be the software I'm using as I only go to PhotoShop if I have to do more than crop, color balance, and/or resize for web posting. I use Thumbs Plus, it's up to version 8 and I started using at version 3.

When I resize smaller with Thumbs Plus the image always looks sharper, the same with PhotoShop 5. But then again I don't try to save fuzzy photos of mine, I only allow myself one sharping pass if that does not fix the problem it's not saved or used.