One person says to use the crop tool set to 16 x20 inches and to leave the resolution box blank
YES! Do that.
Another person says that by doing that, PS will just use it’s default setting (she said hers was 300ppi) and it will resample. This person is wrong, if you leave the resolution field blank, there is no resampling.
I tried cropping an image with the Crop Tool set to 3" x 3" and no PPI number. Everytime I cropped I got a different PPI depending on the area I cropped. The larger the area, the larger the PPI. The smaller the area, the smaller the PPI.
So I cropped a 3" x 3" area, and the PPI was 300. Then I cropped a 2" x 2" area and it was 200 PPI. 5" crop yielded 500 PPI. So, it seems the default on my setup is 100 ppi with the box left blank.
However, specifying a new PPI for your crop shouldn’t hurt the image. Photoshop does a pretty good job of up-and-down rezzing.
WinXP SP2, CS3
When you leave the resolution area blank, NO resampling is taking place. There is no "default" resolution when left blank. The final resolution of your file depends on how tightly you crop – basically you’re just cropping pixels, and it’s leaving you with whatever pixel dimensions are in the file AT THAT CROP. The only thing the crop tool does at that point is assign your stated dimensions (16 x 20 in your case) to whatever pixels are left. The resolution that is now in your Image Size is simply a reflection of that. The smaller the crop, the few pixels and the fewer pixels per inch. Any time you plug in a resolution number (300 dpi in your case) the crop tool will crop to your requested size but then resample to give you the 300 dpi you also requested, which may or may not be a good thing. You really need to know exactly what is required of the specific printer you are using – more about the real resolution that it needs. For example, LIghtjets can go at either 200 or 300 dpi, but you have to tell the lab which resolution you want. Lambda’s are either 200 or 400 dpi. Optimum resolution for inkjets depends on the printer, the paper and the viewing distance.
Thank you all so much. I am using a pro lab to print the picture. So i would assume I can just send it in with the right dimensions and then let THEM upsize.
tried cropping an image with the Crop Tool set to 3" x 3" and no PPI number. Everytime I cropped I got a different PPI depending on the area I cropped. The larger the area, the larger the PPI. The smaller the area, the smaller the PPI.
That’s to be expected. It happens because no pixels are being added or removed.
Larger area = more pixels, smaller area = less pixels.
Since the size in inches is fixed (in your case 3×3") the resolution varies accordingly.
"So i would assume I can just send it in with the right dimensions and then let THEM upsize."
I never assume anything other that even at so called "pro" labs, most of the people are barely adequate when it comes to technical details. I would find out the exact specs for the printer and not rely on them to do it for you unless you feel they are better at it than you are. You are going to want to sharpen your image for the output size, and if you send them a smaller sized file, the chances of them getting that right are not great. A lot depends on image content, type of print, who is going to look at it and from what distance. I just like to give them the fewest number of places for them to screw up.
Peter –
That’s a pretty sweeping, and, to my mind, unfair generalization. The staff at a pro lab deals with these procedures every day. When I was doing lab work, it was usually the customers who thought they knew better than us, whose jobs caused problems. You should work with your provider, not against them.
John,
It may be sweeping, but it’s been my experience, and not in a small market, but here in Los Angeles. For the most part, labs just can’t afford to hire digital personel who really know their stuff. A&I’s counter help is still telling customers that their Lightjet’s are "calibrated to sRGB. ProOne’s process control is so bad that they have to reprint into the night til they get it right. ColorTek doesn’t do or know about profiles or color spaces, preferring to use proprietary lookup tables that mean nothing to anyone but the guy who made them and their own drum scanner. They all claim to be experts, but they almost always fall short. The closest I’ve found to professional competence in L.A. is The Icon and Bowhaus. Your experience may indeed be different, and other markets may have more professional labs, but here in L.A. the nation’s, what, second or third largest market, they just aren’t that great.
For the most part, labs just can’t afford to hire digital personel who really know their stuff.
That’s cause they all figure lowering the prices of their product is the way to increase sales. They also shifted from investing in employees to investing in equipment like that’s all you need. This means the really competent folk wake up one day and figure they’ve got a dead end job and decide to move on — it’s what I did.
What I do is use the rectangular marquee tool. I select fixed aspect ratio in the tool settings palette, enter 16 x 20, and then make a selection. Unlike the crop tool, this lets me see outside the crop area. If I need to change the size of the selection, it’s easy to do with Select/Transform Selection. You can move the entire selection box by positioning the mouse pointer inside it and dragging.
Once the area is set, choose Image/Crop. Find out the optimal resolution for your lab and then use Image/Image Size to change the resolution to the correct value. After the image is resized, it is a good idea to use the Unsharp Mask tool to sharpen it as changing the resolution will usually blur the image a bit.
Relying on the lab to do all this for you is a bit of a crapshoot. You don’t know how they will scale the image, and whether or not they sharpen. This way you see the image the way you want. Once you have saved it, specifically tell them no sharpening and no resizing.
Remember that if you want a border around the image the original proportions will vary slightly. For a 1/4 inch border, use 15.5 x 19.5 and then once everything is done, use Image/Canvas Size to extend the canvas 1/2 inch with the center box in the grid as the origination point. This will give the desired 1/4 inch border.
The procedure above will work with the crop tool as well, but try both and see which way you like better.
It’s been a few years since I worked at a Pro lab, and am sorry to hear that things have gotten like that. In retrospect, though, I shouldn’t be surprised. The handwriting was already on the wall regarding investing in hardware, but not personnel.
wake up one day and figure they’ve got a dead end job and decide to move on — it’s what I did.
Same here. I would have had to, even if I’d stayed. The lab I worked for closed a few years later, likely due to the constant price undercutting going on between them and their competitors. What was their biggest competitor is now a fifth of its former size, as well.
"One person says to use the crop tool set to 16 x20 inches and to leave the resolution box blank. By doing so, it will crop the ratio right without resampling the image."
The above is the correct answer.
Robert
"Unlike the crop tool, this lets me see outside the crop area."
Don’t know about your Crop Tool, but mine lets me see beyond the cropped arrea in any opacity I choose. That’s feature’s been with us for several versions now. Not only that, you can rotate and do a perspective crop and crop outside your image, adding canvas area with background color during the crop. The crop tool is so much more versatile, I’m not sure why you would want to use the marquee tool.
Whether or not resampling occurs upon cropping via the crop tool with the resolution box left blank depends on the units used in defining the resultant printed cropped image. If PIXELS are used to define size in the crop tool options bar, the pre-existing resolution is preserved and, for this to take place, resampling is forced. If inches or centimeters are used, no resampling occurs and the resolution will change, increasing as the box is dragged out and decreasing as the box is contracted—using only the original pixels within the cropped outline. Of course, for that to happen, the individual pixels change in size.
Peter,
"…The crop tool is so much more versatile, I’m not sure why you would want to use the marquee tool…"
I agree. The crop tool can do anything that cropping via the marquee tool can do and so much more. The marquee tool approach, however, has simplicity of concept on its side. It corresponds to cutting out a portion of the original image as if taking scissors to it. If that’s all you want to do, it is direct and straightforward and isn’t going to confuse anyone.
George
Hi to all,
Special thanks to Peter F.! Your explanation (re: post of July 26th) is the first that finally made sense to me. Have been searching the web about cropping/resolution/resampling issues for days and just didn’t seem to get my head round it ’cause of not finding the answers I was looking for.
Was experiencing similar probs to Bonnie’s, cropping my images as close as possible to the actual document size as given in the Image Size dialog box (at a resolution setting of 300 ppi), to ensure the least amount of pixel loss. E.g. if I have an original Tiff which has a pixel size of 3072×4096 and therefore a document size of 26,01cm x 34,68 cm. (10,24"x13,65") at 300 ppi, I would set the crop width and height to approx. 25 x 35 cm and the resolution at 300 ppi.
By doing this and by reading what you said, Peter, I do think that I am resampling slightly by doing this, right? I did several tests, also leaving the resolution box empty when setting the crop size, but this seems to cause more pixel-loss.
Would you like to share your thoughts on this?
I am using PS CS3 Extended and generally have to make large prints (50 x 70 cm.) using a professional Photolab.
Thanks in advance!
Cheers,
Canoë
www.2GoBelow.com
By doing this and by reading what you said, Peter, I do think that I am resampling slightly by doing this, right?
you are certainly resampling (unless you happen to crop an area that is exactly 25 x 35 cm on your original image)
I did several tests, also leaving the resolution box empty when setting the crop size, but this seems to cause more pixel-loss.
try this: take two copies of your image, crop one with the resolution set at 300 ppi, then crop the other with the resolution left blank and use image size to resample up (or down) to 300 pi.
Thanks Cybernetic Nomad!
I will try this out and let you know the outcome…
Which method would you personally prefer?
Cheers
From a practical point of view, if one crops without resampling and winds up with a ppi that is inadequate, you will have to resample anyway, so what I do is crop a dupe file to size and work with that. You do have the same choices cropping as you do in the Size box anyway. Further, in many cases, after a crop, I wind up with numbers like 237.774 ppi, not exactly what you want to send to the printer.
Sorry to hear about LA. In Portland, we have three very good labs, make that four. They all encourage you to pre- flight your images, providing soft proofing for your assistance. Some even offer a financial incentive to simply open the file and send it to the printer. If you want them to do that final work, they offer and urge a proof print first. But even there and I did run a 9800 for a fledgling lab until it closed. Just like in a chemical print process, I preferred to tweak after seeing the proof, and it’s far better having a fine printer on hand to do that first. Then if I want something bigger than my 3800 can deliver, the file and the final presentation goes to the lab.
There is yet a caveat here. I did a print at about 11×14 on the 3800, a b&W and it looked perfect, so I resized and printe at 16×20. The image picked up density and contrast in that transition, Now, I will crop a small portion at the desired size and proof with that.
I have no idea at the moment why this is so.
Which method would you personally prefer?
I prefer to crop and then do the resampling myself, that way I know what’s going on.
