Question about cropping

[markperez]

When you crop in PS and select say 4x6 at 300 pixels/inch if you ask for a 8x12 print of that photo is it also going to be 300 pixels/inch or is the pixel/inch going to be less? Hope I am making sense with this question

[dab94]

If you *tell* it to crop at 8x12 and 300dpi, then that's what you'll get.
If you crop it to 8x12 and don't tell it 300dpi, then your dpi will go down (I think).

Also, crop from the original, not from the 4x6 for best results.

[jeffkohn]

Originally Posted by markperez

When you crop in PS and select say 4x6 at 300 pixels/inch if you ask for a 8x12 print of that photo is it also going to be 300 pixels/inch or is the pixel/inch going to be less? Hope I am making sense with this question

With photoshop if you enter both a size and a PPI, it will actually interpolate to the specified PPI. For instance, set the crop tool to 4x6in at 200 PPI and crop. The set the crop tool too 8x12in at 200PPI and crop the whole thing again. You'll find that the image size changed considerably with both crops and not in a good way. I leave the PPI blank because I'm only interested in cropping, not interpolating.

[markperez]

Originally Posted by jeffkohn

With photoshop if you enter both a size and a PPI, it will actually interpolate to the specified PPI. For instance, set the crop tool to 4x6in at 200 PPI and crop. The set the crop tool too 8x12in at 200PPI and crop the whole thing again. You'll find that the image size changed considerably with both crops and not in a good way. I leave the PPI blank because I'm only interested in cropping, not interpolating.

So Jeff if I set the crop tool to crop at 4x6 and leave the PPI blank I can then take that photo and have it printed at 8x12 and be fine?

dab94 not sure if I am making myself clear. I will crop the photo to 4x6 and save it as a jpeg. I then want to take that photo that is cropped to 4x6 and have it printed as 8x12. Being that this is a 2:3 ratio would the print be ok?

[jeffkohn]

So Jeff if I set the crop tool to crop at 4x6 and leave the PPI blank I can then take that photo and have it printed at 8x12 and be fine?

As long as the image has enough resoultion. DPI will drop as print size increases. If you're talking about a 6MP image then yes an 8x12 print will look great.

The reason you don't want to set the PPI when cropping to 4x6 is because that would actually make the image smaller, since 6MP at 4x6 is over 300dpi. You don't want to throw away that image data, especially if you plan on printing larger.

[markperez]

Thanks Jeff

[suzyjazz]

Am I the only one who doesn't use the crop tool? I have always drawn the selection box (with an aspect ratio defined) and used Image > Crop in the menu. Then use Image > Resize to resize it to my print size. For 4x6 this just throws pixels away when I prep RAW files. They have a default dpi of 240 in the Image Resize box settings, which is very sufficient for 4x6 so I leave alone. If I have cropped a lot out or I am making an 8x10 or larger, I make sure to uncheck the Resample Image box to prevent interpolation and keep an eye on the resolution to make sure it doesn't go too low. I think this is the same thing, just a harder way to do it.

[janetg]

i don't even do that ...

i set the crop ratio...for 2:3, or 4:5, or 5:7 and then crop - photoshop takes care of the dpi for printing, it's in the preferences...


if you do any outside printing, the printer drivers will take care of the dpi...

at least, this is my impression...

janetg

[jeffkohn]

Am I the only one who doesn't use the crop tool? I have always drawn the selection box (with an aspect ratio defined) and used Image > Crop in the menu.

I guess it's just what you're comfortable with. To me that seems like an extra step since I tend to avoid menu commands.

Then use Image > Resize to resize it to my print size. For 4x6 this just throws pixels away when I prep RAW files. They have a default dpi of 240 in the Image Resize box settings, which is very sufficient for 4x6 so I leave alone. If I have cropped a lot out or I am making an 8x10 or larger, I make sure to uncheck the Resample Image box to prevent interpolation and keep an eye on the resolution to make sure it doesn't go too low. I think this is the same thing, just a harder way to do it.

The only resizing I do in Photoshop is down-rezzing for web display and that's to a separate file. Other than that I want to keep my "master" image at its original resolution since I wouldn't ever want to throw pixels away only to regret it later if I decide to print larger. Also the only cropping I do in Photoshop is for compositional purposes.

For printing, I use QImage. It handles interpolating and sharpening for output, automatically optimizing for the printer's native resolution. It also allows you to adjust the page layout in the case where the image dimensions don't match the output dimensions, basically allowing you to adjust the crop on the fly for printing without altering the original image.

[Collins]

When I use the crop tool, it's specifically to save a *different* file that I can upload to printers such as Mpix or Winkflash.

300dpi is plenty for a 4x6 or 5x7 to my eyes and also my customers. Even though I have a 50KB/s upload on my connection, it still saves time to use smaller files when possible.

For the original poster:

If you set your *original* file to to be cropped to 8in by 12in 300dpi in photoshop, you will get a file that will yield a good looking print. The crop tool is designed for simplicity--input what you need and that's what you get. Make sure you save this to a seperate file as to preserve all the pixels of the original.

[Nevyn]

Okay, dumb question time.
Why would you crop and size to 4x6 and then try and print at 8x12?
Wouldn't you get a better print quality to size it to 8x12 in the first place? (have either multiple copies of the processed image at different sizes - afetr all you may want to tweak the different size individually - or keep the larger one and just print at a smaller size.)

It seems strange to make the image smaller and throw away data to then effectively enlarge it again to print?
What am I missing?

[janetg]

this is why i use crop ratios....it keeps your basic file size more or less the same - minus the cropped portions...

i think most people don't understand the ratio thing either - it's fairly basic... 8x12 divided out to a 2:3 ratio - so either way - you get the crop size you want - leaving inches and pixels out of it...

janetg

[Nevyn]

Janetg, the ratio thing I get, the resizing thing seems like a waste to my eyes anyway.

Thanks for the response.

[janetg]

i agree, i never resize...

i was hoping they would get that as well...

i do understand that people have sent prints off to costco or other places, and have had parts of their photos cut off - because they don't understand how to crop..

for those of you that do - always keep your original file intact...after cropping, you can rename with say like DSCF.....4x6 or something like that to differentiate it from your original...

janetg

[BobbyC]

An even better solution is to use Qimage to print (or prepare files to print). You never have to crop the original file, just correct as needed, then add to the Qimage que, define the crop for the size you want to print, then print to printer (or file to take to a lab).

Your original files are never touched, Qimage upsizes as needed for the print size, but only does it as it sends to the printer, leaving the file untouched. (You can print to file to take to a lab, but it will be a new file, original will be untouched) You don't have to save different sized files for different sized prints. It will also sharpen at the time of printing (to your liking), but it's a filter, so the file remains untouched. I do all of my own event printing and Qimage makes it a breeze.

The interface takes a little getting used to but it's a great little program, almost like a RIP, except you still use the native printer driver.

I don't have any ties to Qimage, I just think it's worth looking at.

http://www.ddisoftware.com/qimage