printing resolutions and printing question

JB
Posted By
Jeff_Birgbauer
Aug 10, 2004
Views
383
Replies
21
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Closed
i’m designing a DVD cover for an independant film. the only problem is the images i’ve been given are 72 not 300. the main picutre is huge however, how will this look when printed?

then i’ve combined it with another image that is at 72 but much smaller , so i’ve had to enlarge it, plus i distorted the image. how will that print?

of course my photoshop document is 300 or should it be 150

also if i change an image to "screen" instead of normal, is it gong to print the same way as let’s a ‘normal" images with an 85% opacity or is the screen going be dot-like?

ps. i’m just getting back into the graphc design field after a lenthly absence.
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print question resolution

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MO
Mike_Ornellas
Aug 10, 2004
how will this look when printed?

like crap.
JB
Jeff_Birgbauer
Aug 10, 2004
that was helpful…
DH
Donna_Hanken
Aug 10, 2004
I’m sorry, but I’m probably not going to be much help either. However, I do know that 72 dpi is simply not meant for printing, it is best suited for the web. Unfortunately, I don’t think it will print well at all especially the one that you have to enlarge. Are these digital photos or scanned? Is there a negative or original photo you can get your hands on?

Good luck..
GB
g_ballard
Aug 10, 2004
make a new PS document at the correct dimensions at 300 ppi

open your existing file(s) and drag its image into the new document window (it will automatically drop there at 300ppi)…then use Transform (Command+T) to fit the image…this is a round-about way but
DH
Donna_Hanken
Aug 10, 2004
So you’re saying an image that was originally 72 dpi can be turned into a 300 dpi image simply by dropping in into a 300 dpi photoshop document??? i did not know that…
GB
g_ballard
Aug 10, 2004
ya

notice the document size dimensions change (but the pixel height & width and MegaByte size remain the same)

digital professionals pay most attention to pixel height & width (because resolution can be described in numerous PPI pixels per inch without changing actual pixels)…

for the internet, 72ppi

for print, 300ppi
R
Ram
Aug 10, 2004
So you’re saying an image that was originally 72 dpi can be turned into a 300 dpi image simply by dropping in into a 300 dpi photoshop document???

Yes, but the image will shrink in size accordingly.
GB
g_ballard
Aug 10, 2004
for example:

a 4000×4000 pixel image at 72ppi is 55×55-inches

THE SAME FILE can be

4000×4000 at 4000ppi it is only 1×1-inch

4000×4000 at 300ppi is 13×13-inches
DH
Donna_Hanken
Aug 10, 2004
This is something that has always confused me. For instance, my scanner res is 1600×3200 dpi and my printer’s is 4800×1200 dpi. I usually just scan everything at 300 dpi unless I’m going to enlarge. But I can’t seem to figure out what the maximum amount I should scan at, meaning, I don’t want to over scan if my printer isn’t capable of printing it.
I’ve heard to scan at 1/3 the optical resolution of the printing device being used but not sure exactly how to go about this??? formula??? Which of the above numbers so I use?

Also, how do ppi and dpi’s translate? I know one is pixels and the other dots, but if I scan at 300 dpi is it 300 ppi?

Sorry, I’m not very mathematically inclined.

Thanks in advance
R
Ram
Aug 10, 2004
Let me take this out of order because it will make more sense that way.

how do ppi and dpi’s translate? I know one is pixels and the other dots, but if I scan at 300 dpi is it 300 ppi?

You do NOT "scan at 300 dpi"; you scan at 300ppi. Images never have dots, they have pixels. Only the printer deals with dots.

This is something that has always confused me. For instance, my scanner res is 1600×3200 dpi and my printer’s is 4800×1200 dpi. I usually just scan everything at 300 dpi unless I’m going to enlarge. But I can’t seem to figure out what the maximum amount I should scan at, meaning, I don’t want to over scan if my printer isn’t capable of printing it.

You can scan up to the maximum resolution of your scanner, which in your case is 1600ppi. (Forget about the "x3200" ppi figure, that is not optical resolution and it’s totally irrelevant.)

If you are going to print the image life-size (1:1, or 100%), yes you should scan at the resolution you are going to send to the printer (we’re still talking ppi here). I like 360ppi because my printer prints at up to 2880dpi (now we are talking dots; think dots only when you think ink). 360 –> 720 –> 1440 –> 2880 (you see the pattern here.)
GB
g_ballard
Aug 10, 2004
I scan at my scanner’s Optical Resolution (and target MegaBytes on the large size) <http://www.gballard.net/psd/16bitworkflow.html>

Then repurpose for…
<http://www.gballard.net/psd/sharpening.html>

ppi v dpi
that’s one for a rocket scientist (but most people won’t spaz on us if we mix them up because they are the same, in a general loose sense). it just shows we don’t really understand the point….

PS: Ramón, mine is shorter so I must have took more time to write it 😉
JB
Jeff_Birgbauer
Aug 10, 2004
thanks so much, but sadly it makes the image too small for what i need it for. can i just change the resolution of the document and resample it?
DH
Donna_Hanken
Aug 10, 2004
Thanks for the replies it’s starting to make more sense…

However, my Epson scanner refers to EVERYTHING in dpi. It says 1600×3200 dpi. When it lists scanning recommendations, it lists them in dpi. Also, where I select my res when scanning it says dpi. This is why I’m confused about the ppi/dpi thing. Why does Epson do this?

Logically, yes, I get why dpi would relate to printing (ink dots) and ppi would relate to images (pixels).

Ramón, I see the pattern above but why 360? Why not 720? Sorry , my thick scull is trying absorb how to figure out the best res. Otherwise, I’ll just stick to 300 dpi, I believe that’s what my teacher suggested. Sorry, ppi…

Thanks again
GB
g_ballard
Aug 11, 2004
Epson scanner refers to EVERYTHING in dpi

I get why dpi would relate to printing (ink dots) and ppi would relate
to images (pixels).

You got it, Epson is just kornfused…
R
Ram
Aug 11, 2004
Donna,

However, my Epson scanner refers to EVERYTHING in dpi

Not only Epson makes the mistake of referring to ppi as "dpi". It’s a common misconception that has acquired a life of its own. It’s just plain wrong, strictly speaking. However, usage is what determines the meaning of a term, and by now ppi and dpi have become freely interchangeable.

If one wanted to be meticulously accurate, one would speak of "spi" (samples per inch) when referring to scanners and scanning, ppi when referencing the digital images and dpi for printing. But, why fight it? Huge numbers of people use dpi and we know what they mean just as well.

I see the pattern above but why 360? Why not 720?

Simply because it’s overkill (unless you’re going to enlarge the image, in which case the magnification will dictate the resolution), and it makes for an unnecessarily large file size. In the case of your scanner and my printer, I’d scan at 1440ppi if I needed to print a poster from a scanned 8×10 print, for instance.

Yes a lot of people suggest 300ppi is enough, but the teachers and world-famous photographers I know insist on 360ppi as a better starting point, because that figure results from dividing the printer’s resolution by an even integer (2x, 4x, 8x. etc) while 300ppi would be dividing 2880dpi by an inelegant factor of "9.6".

This is why I’m confused about the ppi/dpi thing.

Here’s an excellent aid to make you understand it all with absolute clarity, and to enhance your scanning skills exponentially:

<http://www.scantips.com/>

The site is huge and there’s a printed version available (which I bought, by the way) for $24; but the entire contents are online –for free.
GK
Gerhard_Kuhn
Aug 11, 2004
When resizing the image by changing the DPI of the image make sure that the resample box has been unchecked. If you do not do this PS will maintain the physical dimensions of the photo through interpolation which will always degrade the image.

As far as I understand scanning prints beyond 600 dpi/ppi is a waste of mb since photos printed by photo labs are not processed at resolution beyond that (typically 400 to 500). Generally when scanning a printed photo you should limit your enlargements to 2 x the original if you want to maintain near original quality. When scanning film/slides much higher resolution can and should be used because of the small size of the original that is much more densely packaged with information than the second generation print. 35 mm film should be able to produce very high quality 16 x 20 prints and acceptable prints somewhat larger.

Gerhard
JB
Jeff_Birgbauer
Aug 11, 2004
Herard,
it does? it looks the ok to me. i though you are supposed to keep it checked, that adds more pixels or information

so i’m confused can i just change the 72dpi image to 300dpi and keep the resample box checked?
JB
Jeff_Birgbauer
Aug 11, 2004
more confused. what happens if i hit the resample box but uncheck the constrain proportions?. i’m totally confused 🙂

so what should i do to change a 72 image to 300 to get it to point that "might" make a somewhat respectable print image.

guess my other choice is to print these out on color laserjet and scan them at a higher dpi
R
Ram
Aug 11, 2004
Jeff,

guess my other choice is to print these out on color laserjet and scan them at a higher dpi

Now, THAT would be sheer nonsense.

more confused. what happens if i hit the resample box but uncheck the constrain proportions?

Depending on what values you type in, your image will be severely distorted, unless you happen to input data that coincides with the precise aspect ratio of the image.

You know, Jeff, just duplicate the image and try all these ideas you are inquiring about. You’ll learn a lot that way.

so what should i do to change a 72 image to 300 to get it to point that "might" make a somewhat respectable print image

Re-scan the original at a higher sampling rate (higher ppi).

Study the information in the link I provided above:

<http://www.scantips.com/>
AW
Allen_Wicks
Aug 11, 2004
Regarding "thanks so much, but sadly it makes the image too small for what i need it for. can i just change the resolution of the document and resample it?" the general answer is no. You generally cannot magically create more image data. And scanning degrades images, always making things worse not better.

The exception to "You generally cannot magically create more image data" is the truism that well shot (!) SLR digicam images can typically be uprezzed 100-200%.

As I recall "Photoshop Classroom in a Book" has a decent discussion of dpi/ppi issues.
DH
Donna_Hanken
Aug 11, 2004
Thank you SO much it’s clear to me now why I was so confused. And thanks for the links and all the helpful info.

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