[Week 10] Case Study 3

The Horrible Mistake of DPI!!

the topic sounds horror? yes..it is horror~

in class, when discussing the case, we were puzzled..confused…kerut kerut muka…

Dr Z also kelam kabut when explaining..sebabnya tak paham paham studentnya… *sorry doctor~*

the study case is:  a print shop asked a client to only give a photo with 300dpi to be printed. the client resampled an ideal photo from 72dpi to 300dpi without hesitation.

well, to show that i understand better than before *which i doubt..haha*, i’m putting some note here:

1. both fault! the print shop is either having an old printer *which is to be blamed since a print shop should have the latest printer..haha* or did not know the concept of dpi. the client did not know that resampling will just create a pixelate picture.

2. what is dpi? it is DOT PER INCH! the main thing is dpi is for printing activity. as long as the printer can set to 200 dpi or 300 or even 400 and above, it is enough. no matter if the picture is in 72dpi or 300 dpi..the printer can handle it~ *grateful to live in this high technology world..haha..*

3. Don’t resample! Don’t enlarge! it is a BIG NO to designer, photographer and should be THAT PRINT SHOP MAN too… resample will just make the pixel pixelate and be grainy.

4. the best way *if the shop insist to accept only 300dpi photo and it is the only print shop in town* is to play with the resolution or the resolution. change the resolution may give you a smaller picture but it is ok. printer can transform it to be nice!

What Print Shops Really Mean by DPI :Back to our print shop – if they are looking for a digital photo to print at 10 inches by 8 inches, at 300 PPI, then they are really looking for a digital image with a resolution of 3000 pixels by 2400 pixels (regardless of the DPI setting of that image).

What Print Shops Really Need: The concept that 300 PPI = photographic quality is also a holdover from the quality of printing equipment a decade ago. Present day printers will output a good quality digital photo, with “photographic quality” at 200 PPI – so the requirements for a 10 inch by 8 inch paper photo become a good quality digital image with pixel dimensions of 2000 pixels by 1600 pixels.

some points to remember (especially in our exam..haha):

1. there are several main factors that determine image quality:

1) The quality of the recording device (camera’s optics and sensor, scanner’s sensor).
2) The size (in pixels) of the digital image.
3) The digital format it is stored in (lossless vs lossy compression).
4) The technical proficiency and the “eye” of the photographer.

5)a photo that has not been enlarged either in post-processing or by in-camera digital zoom (never (ever) use digital zoom).



2. a method to play with the pixels (picture above).

3. To be clear, neither the DPI or PPI setting in a digital photo changes the digital quality of that photo. The resolution of a digital photo is its pixel dimensions.

references:

notes from dr

http://www.rideau-info.com/photos/changedpi.html

http://www.photos8.com/dpi.html

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