12 Replies Latest reply on Jan 27, 2010 12:17 PM by Jacob Bugge

    pixel width

    iamtigerlily2

      Hi

      I've been asked to make a graphic which will be used eventually as an avi file. the size is 288x 64pix  with a pixel width of 57.6. save as a jpeg. I have sorted out the size, but I'm at a loss as to what pixel width is and how to set it up. ( I'm not even sure if its done in Illustrator?)

      Can anybody shed some light on this for me?

        • 1. Re: pixel width
          Jacob Bugge MVP & Adobe Community Professional

          iamtigerlily,

           

          I believe it means that you should (steps for your convenience), using pt/px as the unit:

           

          1) Create the artwork in the size 288 x 64 pt/px (this corresponds to the size of the JPEG when shown at 72 PPI being 4" by 8/9");

          2) Reduce the size by a factor 5 (to get a width of 57.6 px corresponding to 0.8" at 360 PPI);

          3) Export the artwork to JPEG at 360 PPI.

           

          In 1), you may work in integer values; with 2) and 3) you reduce the size and increase the resolution correspondingly.

           

          Whoever gave you the task could have said: Create a JPEG that contains 288 x 64 px and has a width of 0.8" and a resolution of 360 PPI. You may ask to make sure.

          • 2. Re: pixel width
            shunithD Level 3

            Hi...

             

            I thought a pixel had no size... therefore, 288 x 64 is all the size that needed to be given... specially, as this is not for press but video???

            • 3. Re: pixel width
              iamtigerlily2 Level 1

              Ok sounds alright, but when you say reduce by a factor of 5, Do I use the scale option or is there another way?

              • 4. Re: pixel width
                JETalmage Level 6
                I thought a pixel had no size...

                "By a factor of 5" is not a size. It's a scale.

                 

                ...but when you say reduce by a factor of 5...

                Reduction "by a factor of 5" could be taken to mean "reduce by 1/5," which would be equivilent to "scale by 4/5", which would (much more clearly) equate to 80%. 80% of 72 PPI would be 57.6 PPI.

                 

                But I have no confidence that's what the strangely stated requirement is talking about. So I'd ask the guy, "What are you talking about?"

                 

                (There is such a thing as non-square pixels.)

                 

                JET

                1 person found this helpful
                • 5. Re: pixel width
                  Jacob Bugge MVP & Adobe Community Professional

                  iamtigerlily,

                   

                  ... but when you say reduce by a factor of 5, Do I use the scale option or is there another way?

                   

                  There are different ways of scaling (Object>Transform>Scale being an obvious one), but I did mean scale.

                   

                  And I did mean scale to 1/5 the size, taking it that the final width should be 0.8".

                   

                  However James is right, there may be a different interpretation, namely that whoever gave you the task is erroneously treating pixels as points (thus meaning 1px = 1p1, in other words 72 px = 1", giving 72 PPI); and that could give the other meaning, namely that the PPI should be changed to 72/0.8 = 90 PPI. I hope that is not the case.

                   

                  You could ask the simpler question: What is the final width and height of the artwork in inches?

                   

                  If my interpretation is right, and whoever gave you the task is not making actual errors, the answer would be 0.8" x 8/45"; if the alternbative interpretation is right, the answer would be 2.3" x 32/45". As I said,  I hope the latter is not the case.

                  • 6. Re: pixel width
                    JETalmage Level 6

                    And I did mean scale to 1/5 the size, taking it that the final width should be 0.8".

                     

                    Scaling to 1/5 the [original] size would be .2, not .8.

                     

                    JET

                    • 7. Re: pixel width
                      Luke Jennings Level 4

                      When you create a new file in Photoshop, one of the options, under Pixel Aspect Ratio: is Square Pixels.Square Pixels.png

                      I miss-read your post, I thought you wrote "There is no such thing as non-square pixels"

                      1 person found this helpful
                      • 8. Re: pixel width
                        Jacob Bugge MVP & Adobe Community Professional

                        James,

                         

                        Scaling to 1/5 the [original] size would be .2, not .8.

                         

                        In my original calculation, in the first post, I suggested:

                         

                        1) Create the artwork in the size 288 x 64 pt/px (this corresponds to the size of the JPEG when shown at 72 PPI being 4" by 8/9");

                         

                        and scaling that to 1/5 yields 0.8", as mentioned further:

                         

                        2) Reduce the size by a factor 5 (to get a width of 57.6 px corresponding to 0.8" at 360 PPI);

                        • 9. Re: pixel width
                          iamtigerlily2 Level 1

                          thanks for the helpful replies, I made the file as was suggested and sent it off to him.... and got a reply asking for a different sized image in an ai format! Which would have caused me much less stress! But Thank you all for the help, this forum has been such a lifeline for me at times.

                          • 10. Re: pixel width
                            Jacob Bugge MVP & Adobe Community Professional

                            For my part you are welcome, tigerlily.

                            • 11. Re: pixel width
                              JETalmage Level 6

                              Jacob,

                               

                              "Reduce by a factor of 5..." in your original post means (because you stated the original and resulting values) reduce by 20% (in other words scale to 80%).

                              But if someone "scales to 1/5" as phrased in your later post, they will scale to 20%.

                               

                              "Reduce by" and "scale to" mean very different things.

                               

                              JET

                              • 12. Re: pixel width
                                Jacob Bugge MVP & Adobe Community Professional

                                James,

                                 

                                What I wrote was, comparable values emphasized):

                                 

                                1) Create the artwork in the size 288 x 64 pt/px (this corresponds to the size of the JPEG when shown at 72 PPI being 4" by 8/9");

                                 

                                and scaling that to 1/5 yields 0.8", as mentioned further:

                                 

                                2) Reduce the size by a factor 5 (to get a width of 57.6 px corresponding to 0.8" at 360 PPI);

                                 

                                I use reduce by a factor in the same (or should I say opposite) way as increase by a factor.

                                 

                                This may be seen as one of many instances of discrepancy between what one believes to have said and the other believes to have heard.

                                 

                                Every now and again I have been called terse or obscure. I am working on it, but sometimes when I relax my statements become too understandable. Not this time, apparently.