Cropping and Printing - please help

Lesley BrayLesley Bray Registered Users Posts: 143 Major grins
edited August 6, 2009 in Finishing School
Please save me from tearing my hair out over this fundimentally basic question. Do you have to resize your image to print? How do you crop and print successfully? I have CS3 and a Canon 40D.
For example my images are 3888x2592 pixels.
After a lot of reading, I believe if I make the resolution 300 pixels per inch it is suitable for printing. I also tick constrain proportions as I do not want the image resampled. This reduces the image document size to 12.96 x 8.64 but I want to print a 10 x 8.
I also need to crop off some of the background.
Now if I use the crop tool and set it to 10 x 8 - I believe my image is resampled and this is not a good thing?
Should I use the Rectangular Marquee Tool at Fixed Size to resize my image?
How do you guys resize your images to print ? I always keep and view my images on pc and never had to think about this before.
This is driving me crazy and I am sure I am thinking along the wrong lines.
Thanks Lesley

Comments

  • pathfinderpathfinder Super Moderators Posts: 14,708 moderator
    edited August 5, 2009
    Lesley,

    I do most of my printing today from Lightroom2, as I like its interface very much. But I have printed from Photoshop for a long time, so I can do that also.

    I store my files as full size RAW files, but I print from edited jpgs, either 8 or 16 bit.

    If my original file is approximately within 200-400 pixels per inch of my final desired print size, I do not change anything in my file, but simply let the printer driver in Photoshop do the image size manipulation.

    In other words, if the longest dimension of my file is 5000 pixels, then the largest image I would print without uprezzing in some manner, would be about 5000 pixels/ 200 pixels per inch = ~25 inches. I know some folks worry about whether it is 240 ppi, or 300 ppi, or 360 ppi, but I have printed each of those ppi ratios to a series of photos and find that I cannot see any difference when I print to my Epson 3800 via Lightroom2. Bear in mind that each image pixel will actually be rendered by the printer driver to 5 to 15 dots of ink ( or even more ) so the dots per inch is still very high.

    If you are printing large - say 30 by 40 inches or bigger, many folks routinely print those as low as 180 pixels per inch, since prints of this size are not usually examined at a viewing distance of 8 inches.

    Now if you only have 2000 pixels, at 300 ppi, you can only print an image of about 6.6 inches at a 300ppi without uprezzing your image. 2000/300=6.66 inches. Smaller images need higher ppi ( say 300 ppi ) because they are going to be examined at such a close viewing distance.


    I wrote a little tute about image sizing here -


    As a practical matter, I have made 16 x 20 pints from about 1/4 of the area of a 40D sensor data after uprezzing, with what I think is a good rendering. I do not recommend this, and the original file must be very sharp and of good quality, but it is possible with modern cameras used appropriately. This is the image from 1/4 of a 40D's sensor
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • Lesley BrayLesley Bray Registered Users Posts: 143 Major grins
    edited August 5, 2009
    Thanks Pathfinder
    Thank you Pathfinder for taking the time to explain this to me - it's all starting to make sense to me now - just needed you to spell it out for me.
    I had read and printed out your very helpful tute before asking for help but I was still having problems getting my head around it all - therefore I was hoping you would be the one to reply as I found your tute very easy to follow.
    Also read a reply to someone having the same problems in Darren Rowse's Digital Photography Forum where it explained you are not resizing to a print size but to a ratio - that helped too.
    It's all starting to come together for me - just have to put it into practice.
    Thanks
    Lesley
  • pathfinderpathfinder Super Moderators Posts: 14,708 moderator
    edited August 5, 2009
    I think the important thing to understand is what it the largest size image you can print with the total number of pixels you have for a given pixel per inch in the final print. I don't try to resize my image file for each print, as long as I have "enough" pixels for an acceptable ppi ratio in the final print.

    You get to choose the pixels per inch that you feel is good enough, whether 180 ppi, 200 ppi, 300 ppi, or 360 ppi. But one of those is the ratio you will have to use to compute what is the largest print you can make with your image file without uprezzing. As long as the ppi is reasonable, I let the printer driver do the actual final changes for a given print size. I do not resize my image for a different print size, unless the number of pixels I have is inadequate. I let the printer driver do it in Lightroom2, and it has not let me down so far.

    I suggest you print out a series of prints at 180ppi, 200ppi, 300ppi, and 600ppi from a given file, and look at them and see if you can identify which is which, if they are not labled. A blind study in other words.

    If I do not have enough pixels, my first response is to return to my RAW file, and interpolate it when it is converted into a tiff or jpg from inside the RAW converter. Adobe RAW converter offers you a choice as to the final image size created in the conversion from RAW to Photoshop. If that is too small, then I will uprezz with Genuine Fractals 6, because that is the uprezzing software that I have owned for several years. There are lots of other choices, but that is what I have used with some success.
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • TonyCooperTonyCooper Registered Users Posts: 2,276 Major grins
    edited August 5, 2009
    Please save me from tearing my hair out over this fundimentally basic question. Do you have to resize your image to print? How do you crop and print successfully? I have CS3 and a Canon 40D.
    For example my images are 3888x2592 pixels.
    After a lot of reading, I believe if I make the resolution 300 pixels per inch it is suitable for printing. I also tick constrain proportions as I do not want the image resampled. This reduces the image document size to 12.96 x 8.64 but I want to print a 10 x 8.
    I also need to crop off some of the background.
    Now if I use the crop tool and set it to 10 x 8 - I believe my image is resampled and this is not a good thing?
    Should I use the Rectangular Marquee Tool at Fixed Size to resize my image?
    How do you guys resize your images to print ? I always keep and view my images on pc and never had to think about this before.
    This is driving me crazy and I am sure I am thinking along the wrong lines.
    Thanks Lesley

    My answer is quite a bit less complicated than Pathfinder's, but probably less technically sound. I don't resize the image in Photoshop. I set the crop at the dimensions that I want the print to be and the ppi at 300. I then "save as" and give the cropped image a new name. (This allows me to keep the image in the original size and later crop it to a different ratio.)

    I don't know of any valid reason to prefer to resize rather than to crop. By saying so, I'm sure I'll bring out the valid reason from someone else, though.

    PS I could crop in Bridge or Lightroom, and undo the crop later, but I prefer to crop after converting the image to a .jpg. It means an extra file (the original .jpg and the "saved as" cropped .jpg, but that's what I prefer.
    Tony Cooper - Orlando, Florida
    http://tonycooper.smugmug.com/
  • pathfinderpathfinder Super Moderators Posts: 14,708 moderator
    edited August 5, 2009
    TonyCooper wrote:
    My answer is quite a bit less complicated than Pathfinder's, but probably less technically sound. I don't resize the image in Photoshop. I set the crop at the dimensions that I want the print to be and the ppi at 300. I then "save as" and give the cropped image a new name. (This allows me to keep the image in the original size and later crop it to a different ratio.)

    I don't know of any valid reason to prefer to resize rather than to crop. By saying so, I'm sure I'll bring out the valid reason from someone else, though.

    PS I could crop in Bridge or Lightroom, and undo the crop later, but I prefer to crop after converting the image to a .jpg. It means an extra file (the original .jpg and the "saved as" cropped .jpg, but that's what I prefer.


    What if your file does not have enough total pixels for your final desired image size at 300ppi? Where do those extra pixels come from then? Interpolation?

    If you are only cropping to a particular ratio, but not a specific size, I think that is fine.

    Or do you just not ever print large enough for this to be a concern, Tony?
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • TonyCooperTonyCooper Registered Users Posts: 2,276 Major grins
    edited August 6, 2009
    pathfinder wrote:
    What if your file does not have enough total pixels for your final desired image size at 300ppi? Where do those extra pixels come from then? Interpolation?

    If you are only cropping to a particular ratio, but not a specific size, I think that is fine.

    Or do you just not ever print large enough for this to be a concern, Tony?

    I knew some un-soundness would be pointed out. I have never printed an image (or ordered a print) larger than 8 x 10 or 8.5 x 11.

    The OP mentioned 10 x 8, so I kinda assumed he's concerned about either resizing or cropping images to that size. In which case, I'd crop.

    The only time I use re-size is when I add canvas for some border effect. Then I'll re-size back down to my chosen print size.
    Tony Cooper - Orlando, Florida
    http://tonycooper.smugmug.com/
  • Lesley BrayLesley Bray Registered Users Posts: 143 Major grins
    edited August 6, 2009
    Thank you so very much again for taking the time to explain Pathfinder.
    I have printed this thread out and studied it and re-read your tute - it all makes sense to me now.
    Thank you also to Tony.
    Finally I understand. Maybe I can help someone else now - that would be funny!
    Lesley
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