What is the lowest ppi you can use to get quality prints?

Discussion in 'Digital Darkroom' started by carlosmiller, May 7, 2007.

  1. Of course I know the general rule is 300 ppi or higher, but I have a few photos
    I took in 2005 when I was only shooting JPG on a Canon 10D that I would like to
    get printed into 8x10s or 8x12s(I've since graduated to a 5D and shoot only in RAW).

    When I open these files, they are originally sized at 11.378 x 17.067 inches at
    180 ppi.

    When I convert them to 300 ppi, they end up sized at 10.24 x 6.827 inches.

    And when I size them to 8 x 12 at 300 ppi, the pixel dimensions go much higher
    than the original file, so obviously this might not be the best idea.

    So now I'm thinking of printing them at 8 x 12 at 255 ppi where the pixel
    dimensions remain the same as the original file.

    Will there be a noticeable difference? I plan to sell these in a gallery so
    quality is extremely important.
  2. On any Epson i use i could not see a major difference between 200ppi or 300 or even 360ppi as many people suggest. You will for sure see a quality lost below 200ppi, depending of the size. I have seen nice 4x6 at 150ppi, and nice poster 40x60inch at 150ppi, but i still like and print everything myself at 200ppi, whatever the size.

    I print for top photographer for there portfolio and exhibition in gallery.
  3. I make 8x10 and 11x14 prints from my old 10D. They are not the best but acceptable at "normal viewing distance". When I have them printed online, I do not bother to resize them; the companies do not like that (they consider it bloat).

    Of course you will see a huge quality increase going from a 10D to a 5D. It is not just about the number of pixels, but their quality.
  4. "... I know the general rule is 300 ppi or higher ..."

    Close enough.

    Anything higher than 300ppi you won't be able to see. Except for taking up for resources, it doesn't hurt though.

    Personally, I find 240ppi the minimum necessary for a great print on detail-rich images. 180ppi is okay for portraits and such at reasonably far viewing distances.
  5. it also depends on the paper. canvas or other rough papers can get by with lower dpi printing resolution than glossy papers.
  6. I print 8x10's from my 10D all the time and they are excellent. Back in the 'dark ages' I printed 8x10's from my D30 (not a 30D) and they were more than acceptable.
  7. It also depends on the prointer. I have foun dthe Canon iPF series ahve more efficient
    algorithms to deal with up rezing and high quality printing than those in the Epson x800
  8. "Anything higher than 300ppi you won't be able to see. Except for taking up for resources, it doesn't hurt though."

    I have a Fuji 4500 that goes 400ppi. It is visually sharper than a Noritsu that prints at 300ppi. I also have the small Sony dye sub that goes 403PPI, but only to 4x6, which looks sharper than my Olympus P400 dye sub at 316ppi. Old Lica standards were to enlarger print at the equivelent of 8 line pairs/mm which is about 400ppi.
  9. The above being said, I've seen several Epson 7000 printed sheets at 24" on the short side from a Canon 5D that looked pretty good from a small distance.
  10. 50ppi for a billboard viewed from the freeway. It's okay to up sample a photo to 300ppi. I
    print 8mp files at 16x20 300ppi all the time.
  11. Most folks are usually off an order of magnitude in waht really is required; sometimes even two. A freeway billboard at 50 ppi is massive overkill; its like cutting your grass with a micrometer and sissors. a 50 number is commou with hockey dasher boards; court case exhibits; even rock posters. For a billboard a 3 to 6 ppi image is often quite normal. For precision mapping here we print often above 300; say 400 to 450 if required. This requirement is based on the font size; font style of dinky roads and features. A image with impact on a billboard at 6 pixels per inch on a 12x48 foot billboard is 864 x 3456 pixels; this has more resolution than most folks computer screens 18 inches way from your face. Folks should run actual real world tests instead of getting lost in 255 versus 300 numbers.
  12. All this ppi requirement stuff is NOT rocket science. If you think an image looks swell at 300 ppi when viewed at 1 foot; a billboard then at 100 feet away will look just as swell at 300/100 = 3 ppi. A 50 ppi number for the billboard would mean you are looking at it at 6 feet away; like a billboard installer; bird; or person about to run into the sign. If the interstate sign is viewed 300 feet away; a ONE ppi image is totally fine; actually overkill since you are in a fast moving car.
  13. I have hung prints in exhibitions that were well received (and sold) which were printed at
    100 ppi. More important than density alone is the kind of picture you are presenting and
    the overall size.

    Basically, what I find is that digital capture, digitally printed photos look better and better
    as they are printed larger up until the point that pixelation becomes visible. That depends
    to some degree on the subject matter, to another degree on the viewing distance, and also
    to some degree on how you have managed the image processing.

  14. It depends on your printer, my cannon can be set to print 4800 dpi...

    You can have your original at 240, and set the output in Photoshop Preferences, Units & Rulers. Set Documentation for Print Resolution and set the resolution for the level you desire....

    Learning to use Photoshop to get the maximum out of it is very important. We can only do that, by reading the documentation, and making a print, to see the results. In a real darkroom, a tech interested in getting the best from a print, may even make 10-20 or more variations of lots of prints when learning to use the equipment. One time when creating a still life of a Chess board and Pieces, I made over 50 prints. Variations were not just for time of exposure and development, but cropping, and finally toning in different colors. When I got what I wanted, made a final toned print for my father in laws Christmas Gift. Position of the pieces was the same as in a chess game he won. Must have spent most of a day on that one image.

    With Photoshop, we have a virtual darkroom, and can do many similar things, much faster. We can use features in Photoshop to "see" on the monitor what the print will look like when printed. But, many have never taken the little bit of time to read the documentation to learn how to do, specific things they desire to do..

    We can ask questions here, BUT, seldom are answers complete, read documentation first, then ask questions about whatever you may not understand in doc's. When you do, any additional information will mean a lot more to you... Personally, with over 60 years of darkroom experience, I still read the documentation. Some of it I print, then highlight sentences which I feel are MOST important. When going back to redo something which I feel is not as good as it could be, reread the highlighted portions. Then, repeat, until important steps are memorized.

    After using computers since 1975, I still believe one of the most important sentences Ive read is:

    When all else fails, read the documentation.

    There is no way that can be repeated too often, until all do it...
  15. wnw


    Hi Carlos,

    Great question. My answer is 240ppi for inkets.

    Danny Chau, one of the Epson print gurus once showed me some prints done at different resolutions and pointed out the huge significance of 360ppi. In basic terms, inkjet printers are designed to print using 720dpi/1440/2880 (doubled each time) and all digital print using inkjets revolves around those numbers. Half of 720 is 360 and so 360 is the TRUE ppi for top quality print in sizes A6-A0 using the printer to the best of it's capabilities. (The points made about billboards are the exception for most of us of course and valid points)

    It follows too that 2/3rd of 360 is 240 so this therefore works well.

    Whatever you decide, keep it to what the printer understands the easiest and the starting point in 720dpi - hope this makes sense.

    Likewise, if you print on a dye sub printer that has, say, 400dpi then you can print your images if they are 200ppi. Take the base figure of the printer and work in 1/3rds and 1/2's up or down to suit. It's that simple really.

    What you don't do is print images with say 230 ppi for example as this is not a 1/3 or 1/2 proportion of 720.

    The printer has to do some maths (via it's printer driver) and sending it an image that it can easily divide into 1/3rds or 1/2's produces the best prints. This applies to all printers.

    300dpi is a kick back to litho printing and is completely misused in digital inket printing. 300dpi has nothing to do with inkjet prints in any way at all I'm afraid.

    Ref: Prints are displayed at their ppi (pixels per inch) and prints are made at a dpi (dots per inch)

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