scanning prints & slides

GrahamM

GrahamM

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Under another topic Ray Walton asked about what dpi to scan to. Well,
I don't profess to be an expert on this topic but I do know that a PC monitor can only display at about 72 dpi, which means there is no point scanning at a greater resolution than that for viewing on screen, ie, for web work. However, if you intend to print off the scanned images then you need to scan at about 300 dpi. But as I said, I'm no expert on this topic, so if there is anyone out there who can elaborate on or clarify anything about this topic I'm sure it will be gratefully received by many of us who are not too sure what the exact answers are.
 
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Goose Ganderton

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As you said in your reply Graham it all depends on what you want to do with the end image. A Pc screen has a dpi of 96 and a Macintosh is 72, so if you just want to view images on screen the just scan at thiks dpi but if you want to make prints you need a higher scan but it all comes down to image size and megabytes. the best thing to do is scan the image at the highest resolution that your scanner will record but set the image size to the print size you want. Im a photographer for the national press and the newspapers look for an image to have a file size of about 5Mb but a magazine wants around 20 Mb. If you just want to produce an 8x6 print then go for a 5- 10Mb file size size. If you use something like photoshop you can do a max scan the do your cropping and dpi adjustments in photoshop with a high Jpeg compression. Does that all make sence.
 
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Ray Walton

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Goosy, yoour torkin quacker ingluish If i want to display slides on my own or Grahams website. What dpi do i scan at, to then transport them over to another site? I hear that if you scan them too high ie: dpi 1500-2000 or higher they will take a day to get there, littteraly speaking of course! Also, what is the the best dpi to scan and display on my own imac 64? Did i see you walking to London some time ago or woz i dreamin?....Rollin Ray....
 
GrahamM

GrahamM

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Goose, thanks for the very helpful info, you obviously know your stuff. Ray, for web work I scan slides at 300dpi and then edit them in Paintshop Pro to a pixel size of 200 to 300 pixels down the longest side, the size depending on what size I want them to appear on the screen. I save them as JPEG images with about 50% compression which gives me a file size from about 10k to 25k (again depending on a number of factors)which are small enough to load quite quickly on the web, which is a very important factor. It's no use having large images if it takes an age to download them, for all that happens then is the viewer gets fed up waiting and goes somewhere else. If sending scanned images to me I prefer them sent as bigger files, say 50k to 100k so that I have some leeway to edit them to my own requirements. If scanning just for viewing on your own screen then 300dpi will be okay and saved same size, as a non-compressed JPEG image. Goose will no doubt throw more light on this and correct me if my info is not explained quite right.
 
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steven docwra

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If you want to double the size of a picture without losing picture quality you need to scan it in at double the resolution, this applies for both screen and print. For the screen it is 72dpi and you want to save the files as either jpeg, gif or png. When you want to send the pics to a graphics house for reproduction it wants to be 300dpi or above and either saved as either tiff's or eps files as these don't deteriorate the picture quality like the jpeg compression does.
 
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Gary Knowles

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when anyone finds a company that scans loads of slides, at a high resolution, at a decent price, let me know. I have a couple of hundred need doing !
 
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Cakey

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kin ell this must be the oldest thread on FM..................................
 
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