Post by Big AlPost by DanI plan to scan in some CD covers to a high quality picture.
I would like to take these pictures to a T shirt printers and ask them
to print these pictures onto cotton T shirts.
As far as I know, CD covers are only 300 dpi.
If I enlarge these scanned pictures will I lose detail, that is the
printed T shirts will be block and lose detail.
I plan to scan in at 1200 dpi using my flat bed scanner.
One of the album covers will be a vinyl recored.
It's just basic math. DPI printing or PPI onscreen.
If you scan at 1200 PPI and they print at 300 DPI,
then you can probably afford to print the image
bigger than the 4x4-ish CD size without losing detail.
But it depends on a lot of things, like the quality of
the scanner, the save format, the requirements of
printing, etc.
For example, what if the CD cover was printed at 300 DPI?
Then you'd just be enlarging dots if you scan at 1200 DPI.
Likewise, if you scan but save it as JPG then you'll lose data.
Save as TIF, which is just a compressed BMP, which is what
the original image actually is.
As an ex-printer, when printing images, they are photographed through a
silk-screen to break the images into dots. Newspapers are done with a
very coarse dot, and that is why looking at a newspaper you can see the
dots with the naked eye (given good eyesight).
A printer cannot print black at one point then grey and then white (or
none). There is only black ink. So the silk-screen is used to make
dots, and the dots 'bloom', for lack of another word, and depending on
the amount of light the dot is bigger or smaller. Dots will now be
bigger (blacker) or smaller (greyer). I think I'm making up words here
but....
As Newyana2 says, if you have a 100dpi photo you have garbage and
scanning at 1200dpi will let you see the garbage easier. One dot will
be scanned in as a 12x12 square or 144 total dots.
You're kinda stuck with the quality you have in the original.
Scanning photos is where the 1200 dpi comes in. Kodak photos have no
grain or dot pattern.
The pics were shot though a screen (sometimes silk, but sometimes metal
or wire) because they use "lith" film, with a special lith developer -
so there is no grey scale.
The centre of each dot gets the most exposure, because it’s NOT focussed
on to the film plane, so when its developed (under safelight conditions)
the dot will go black at the centre and then start to grow - you can
watch this happening in real time.
The dots with the greatest amount of exposure will get fatter
I believe they dunk the film in to a stop bath when it reaches the
required density
but ... getting back to the real world, if you think the covers are only
printed at 300 dpi, then you don’t need a scanner because you could get
good enough results from a reasonable SLR
Also ... don’t fall in to the trap of confusing dots with pixels - some
inkjet printers require 6 or 7 dots to create a pixel and I believe the
ratio might be higher on some laser printers.
And ... if you do a google image search, its entirely possible that you
might find a better quality image online somewhere, especially if the CD
was available in vinyl - with any luck it might be free of coffee stains
as well