Previous 1 2 Next 18 Replies Latest reply: Nov 19, 2011 5:59 PM by LawrenceFerr01
LawrenceFerr01 Level 1 Level 1 (0 points)

If I pull 72 dpi photos off the web, will they have poor quality during final playback?


Mac Pro, Mac OS X (10.5.3)
  • David Harbsmeier Level 7 Level 7 (29,825 points)

    DPI is a measurement of the print world and has no meaning in TV or video.  What matters is "pixel dimensions." 72dpi is fine.

     

    -DH

  • Ann Apuladay Level 2 Level 2 (250 points)

    To add to what David said...

     

    I did a test one time, based on a post here a while back on the same topic.  You can do the test too to see for yourself that dpi doesn't really matter in the video world.  I created an image in Photoshop that was 720x480 at 72 dpi, then I made one that was 720x480 at 300 dpi.  Result: They looked the same in FCP.

     

    I have had conversations with my boss about this several times over the years.  It still comes up when we're doing a projected show.  "What dpi are you making your images at so they look the best when they're blown up on the projector screen?" is what he asks.  It's a tough one to explain to people who have spent their lives in the print world.

     

    BTW, if you are going to do any zooming in on the image, the image should be sized larger (dimension-wise) than your sequence settings.  There's a percentage to use that people have suggested, but I don't remember what it is.

     

    Note, a lot of folks here suggest TIFFs over JPEGs.  Some folks like PICTs too.  All RGB of course. 

     

    Hope that helps.

  • Michael Grenadier Level 7 Level 7 (20,325 points)

    This is one of those things that seems confusing.  A higher dpi means that there is more information there (which I assume means a higher resolution).  The question seems to be, how do you convert the graphic so the pixel dimensions will reflect the higher dpi?  Is this possible?  Inquiring minds want to know.

  • Ann Apuladay Level 2 Level 2 (250 points)

    Yes, it is quite the conundrum. 

     

    On the one hand, it makes perfect sense that the more dpi you have, the better the image will look and the more you can enlarge it.  Like, if I put a 72 dpi image in my video and then blow it up on a 10-foot projection screen, you would think that it won't look as good as if I put in the image at 8640 dpi.  (I think my math is bad ... I was thinking 10 feet is 120 inches, and 120 multiplied by the 72 dpi equals 8640 ... that's probably the wrong way to do it but you see what I'm getting at.)

     

    But then on the other hand, you've got plenty of folks on here (and elsewhere on the web) who proclaim, "There is no dpi in video!!!"  Here's a couple links I had bookmarked that support that assertion:

     

    https://discussions.apple.com/thread/2652023?threadID=2652023&tstart=0

    http://www.scantips.com/no72dpi.html

     

    What I've been doing lately is kind of compromising; I make my Photoshop images 150 dpi, and the make sure the dimensions match my sequence settings (720x480, 1280x720, etc.) or oversized if I'm going to zoom in.  Depending on your system, bigger images will slow you down and won't be any noticeable improvement anyway.  Maybe.  Who knows for sure.  It's a gray area to me; Nothing seems to be black and white in the video world.  Except old black and white movies.  Sorry, dumb joke.

     

    You should do some tests yourself.

  • Michael Grenadier Level 7 Level 7 (20,325 points)

    I have done tests.  The question is if you have a high dpi file in photoshop, if you can increase pixel dimension and reduce dpi without losing quality.  I spent a day doing tests years ago and just made myself dizzy.  Maybe I'll return to it.

  • Michael Grenadier Level 7 Level 7 (20,325 points)

    so I did a test in photoshop and yeah, adjusting pixel dimensions and dpi doesn't work.  You'd think there was a way to make this work.

  • Ann Apuladay Level 2 Level 2 (250 points)

    Sorry, I was suggesting that the OP do some tests.  And hey, speaking of OP, I think he should be showering us with thumbs up or gold stars or something since we're devoting so much time to his inquiry.  But maybe I'm just being presumptuous -- maybe I haven't been that helpful.  Maybe the Apple forum people can create a new award icon for when you try to help but it wasn't the best of help.  Kind of like "A for effort." 

  • Michael Grenadier Level 7 Level 7 (20,325 points)

    Ann, get used to it.  I think it's considered bad form (if not forbidden) to ask for points.  And as my father used to say, "that and a nickel will get you on the subway."

  • Ann Apuladay Level 2 Level 2 (250 points)

    Darn, and I was mostly kidding anyway.  I was just thinking about how much time I've spent on this thread instead of doing my work and how it didn't even seem like it was appreciated because the OP hasn't even said anything.  I could remove that "bad form" part of my post, but then your post wouldn't make sense, so you'd have to delete your whole post ... ha ha.

  • Michael Grenadier Level 7 Level 7 (20,325 points)

    once again, get used to it.  Can't tell you how many threads remain "unclosed."  And then there are the threads where the first thing you tell the OP is to delete their preferences.  After days of back and forth, you think to ask, did you ever delete your preferences?  and the answer is....

  • David Harbsmeier Level 7 Level 7 (29,825 points)

    You can adjust one without the other in Photoshop; go to Image->Image Size and enter the desired pixel dimensions (with Constrain Proportions checked).  Note that you shouldn't increase pixel dimensions above original as the quality will suffer, but you can decrease pixel dimensions without problems.  The DPI will remain the same.

     

    However, if you increase or decrease the DPI, the pixel dimensions will also change.

     

    There's a correlation between DPI and pixels built-in to Photoshop, most scanning software and other graphics programs because they were designed that way.  In the scanning software I use (Epson Scan, professional mode), I simply increase the DPI of the scan while watching the pixel dimensions change accordingly.  When I get to the dimensions I want, I scan the image, regardless of the DPI setting.  That way I only have to adjust one number instead of two.  So, depending on the original size of the the image to be scanned*, the final image files I create could be anywhere between 50 dpi and 1200 dpi.  It really makes no difference to FCP, but it gives me the pixel dimensions I need for the edit.

     

    * = images smaller than 2" x 3" may need to be scanned at a relatively high DPI (>600) while images larger than 5" x 7" may need to be scanned at a very low DPI (<72).

     

    -DH

  • LawrenceFerr01 Level 1 Level 1 (0 points)

    Thanks! Very helpfull!

     

    I just logged in after a full day's work, and was unable to write back.

  • LawrenceFerr01 Level 1 Level 1 (0 points)

    THANKS everyone. Very helpful information. I guess I will not worry about dpi, just as long as the dimensions are adequate.

     

    Sorry I was unable to respond till just now. Full day at work today.

  • LawrenceFerr01 Level 1 Level 1 (0 points)

    Thanks for that very helpful and thorough explanation. I feel confident using JPEGS now.

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