300dpi for publishing

Fenman55

Fenman55

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Name
Martin
Edit My Images
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I have been asked to provide some photos electronically [disc or memory stick] for a Construction company, however their publishers say they must be 300dpi.....
What is 300dpi and how do I arrive at 300dpi resolution.
I have checked some of the photos I have for them and they are between 72 and 240dpi, but how they arrived at that number I have no idea!
I am using a 5D mk ii set at the highest setting using both raw and jpeg.
Some were procesed using lightroom 4 and some using zoom browser
 
I'm guessing they want jpeg's ... when exporting from lightroom in the export dialogue, under image sizing there should be an option to set the dpi.
 
300 dpi on its own doesn't mean an awful lot, since it has no reference to image size. They should be expressing the image sizes required (in pixels, mm, points or whatever) because that relates to the end purpose, before stating that they should be at 300 dpi.
 
Ooh, where do we start?

Firstly, when the publishers say the photos must be 300dpi, it's almost certain that they don't know what they really mean by that.

Secondly, any dpi figure embedded in your photos is totally meaningless.

With me so far? Right, now we can move on.

The only thing that really matters is how many pixels you have in your photos. High quality printing usually runs at about 300 pixels per inch (ppi). It follows that if you want your image to print at 4 inches across you need 1200 pixels; 6 inches requires 1800 pixels; and so on.

So what you need to do is:
(1) Ask the publishers what size they want to print the photos.
(2) Resize them to appropriate dimensions based on 300 pixels per inch.
(3) Edit the dpi / ppi value in the metadata to say 300. (This doesn't achieve anything in practice but may keep the publishers happy.)

How to do (2) and (3) depends on which software package you use. The dpi / ppi value is usually an option on the resize dialogue or on the save/export dialogue. If in doubt, ask.
 
Totally agree with the above except they actually mean ppi (not dpi) - ppi oncly controls the print size for any given number of pixels.

PIXELS are all that matter. You could provide a 100pixel x100pixel image at 300ppi - It would print at 0.333"

Stewart's 1, 2, 3 is bang on.

this might help a little although maybe it's more confusing :)
http://www.jbdavies.co.uk/resolution/ppi-dpi/

Cheers
Jim
 
OK thanks everyone, I was aware of the debate but rather than get involved I planned to not get involved and to go with the "clients representatives" flow ie give them 300 dpi whether it is relevant or not.
I have read somewhere that the 300dpi business is so they can export / paste the photos on their documents and all their publishing equipment is set for 300 dpi, so they don't have to make any adjustments....rubbish or not I don't know.
From now on in I am using lightroom 4 for all my processing.

So what you need to do is:
(1) Ask the publishers what size they want to print the photos.
(2) Resize them to appropriate dimensions based on 300 pixels per inch.
(3) Edit the dpi / ppi value in the metadata to say 300. (This doesn't achieve anything in practice but may keep the publishers happy.)

Thanks Stewart, good advice. I suppose I was reluctant because I didn't want to come across as a "plonker".

Thanks everyone
Martin
 
PPI doesn't mean much either I think, as that depends upon the pixel density of the monitor on which you're viewing.
 
Fenman55 said:
OK thanks everyone, I was aware of the debate but rather than get involved I planned to not get involved and to go with the "clients representatives" flow ie give them 300 dpi whether it is relevant or not.
I have read somewhere that the 300dpi business is so they can export / paste the photos on their documents and all their publishing equipment is set for 300 dpi, so they don't have to make any adjustments....rubbish or not I don't know.
From now on in I am using lightroom 4 for all my processing.

Martin
Click to expand...

Not rubbish no, that is possibly exactly why they have asked for them at that size, although it should be PPI not DPI. It is probably easier for their workflow.
 
Fenman55 said:
OK thanks everyone, I was aware of the debate but rather than get involved I planned to not get involved and to go with the "clients representatives" flow ie give them 300 dpi whether it is relevant or not.
I have read somewhere that the 300dpi business is so they can export / paste the photos on their documents and all their publishing equipment is set for 300 dpi, so they don't have to make any adjustments....rubbish or not I don't know.
Click to expand...

Yes- Rubbish lol
Fenman55 said:
From now on in I am using lightroom 4 for all my processing.

So what you need to do is:
(1) Ask the publishers what size they want to print the photos.
(2) Resize them to appropriate dimensions based on 300 pixels per inch.
(3) Edit the dpi / ppi value in the metadata to say 300. (This doesn't achieve anything in practice but may keep the publishers happy.)

Thanks Stewart, good advice. I suppose I was reluctant because I didn't want to come across as a "plonker".

Thanks everyone
Martin
Click to expand...

You cannot change dpi. That's the printer setting the lab control

You can only adjust the ppi setting but all you are actually doing is resampling the image (normally not good).

Here's a great video
 
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EOS_JD said:
The monitor has zero to do wityh ppi.

PPI is a measurement that adjusts PRINT SIZE at any given number of pixels. Nothing else
http://www.jbdavies.co.uk/resolution/ppi-dpi/
Click to expand...

really? I disagree. you don't print pixels, you print dots.
quotes from the link you've posted

Dots & DPIAs you can guess, dpi means dots per inch. Despite what some may say though, this actually has nothing to do with “digital” images at all. Your images are not made up of dots, they are made of pixels.
Click to expand...

Further, look at PPI, I said that it depends upon pixel density, but this also depends upon the size of the monitor too I guess
So if you have a 600 x 400 pixel image it will be displayed using 600 x 400 pixels on your monitor – how large it appears on your monitor will be determined by the resolution your screen runs at. A higher resolution monitor will make the image seem smaller – in reality though it’s still the same size.
Click to expand...
 
DizMatt said:
really? I disagree. you don't print pixels, you print dots.
quotes from the link you've posted
Click to expand...

yes that is correct. PPI only affects the physical print size. The pixels are moved closer together and further apart to make the print larger or smaller. DPI is how the printer lays the dots on the paper.

DizMatt said:
Further, look at PPI, I said that it depends upon pixel density, but this also depends upon the size of the monitor too I guess
Click to expand...

No,
Pixels are mapped on a monitor 1:1 (any monitor). An 800x600pixel image takes up 800x600 pixels on the screen - So if you have a resolution of 800 x600 theoretically the image would fill the screen although your operating system and programs use up some of the pixels to display themselves you would actually see scroll bars as the image is too big to see at full size.

On a 1680 x 1050 monitor the image would take up about half the size of the screen (slightly more) - the actual screen size matters not a jot. Only the resolution of the screen decides how the images are displayed.

The ppi of an image has no effect on how it's displayed on a minitor. PPI ONLY AFFECTS PRINT SIZE - nothing else.
 
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DizMatt said:
PPI doesn't mean much either I think, as that depends upon the pixel density of the monitor on which you're viewing.
Click to expand...

Er, no it doesn't.

Here are images at 10, 300 and 3000 ppi. Note the amazing difference between them.

10ppi.jpg
300ppi.jpg
3000ppi.jpg


ppi is totally meaningless until you come to print an image.
 
:D

My two from another discussion in this yesterday

Which one is 300ppi? and which is 72ppi?
 
StewartR said:
The only thing that really matters is how many pixels you have in your photos. High quality printing usually runs at about 300 pixels per inch (ppi). It follows that if you want your image to print at 4 inches across you need 1200 pixels; 6 inches requires 1800 pixels; and so on.

So what you need to do is:
(1) Ask the publishers what size they want to print the photos.
(2) Resize them to appropriate dimensions based on 300 pixels per inch.
(3) Edit the dpi / ppi value in the metadata to say 300. (This doesn't achieve anything in practice but may keep the publishers happy.)

How to do (2) and (3) depends on which software package you use. The dpi / ppi value is usually an option on the resize dialogue or on the save/export dialogue. If in doubt, ask.
Click to expand...
Stewart has expressed it correctly above, I don't know why everybody else is gibbering on about it?
 
droj said:
Stewart has expressed it correctly above, I don't know why everybody else is gibbering on about it?
Click to expand...

Helpful ;)
 
Well frankly I have to re-assess then... and I have played the 300 and 72 DPI (PPI whatever) game with someone recently with identical images. The software used said DPI.
PPI for me is always pixel density of a display. your phone screen has a PPI rating, have a look at the specs. DPI has always been the actual output.
DPI used to be dots on the page printed but now this is expressed in PPI. okay, times have moved on. I'm pretty sure that it used to be DPI and that's still a legacy in most software packages which is where the confusion lies.
Your referenced article says "Adobe get it right with Photoshop and Lightroom but some software still incorrectly states dpi! No idea why! " Well, I think that's because the term was DPI and then Adobe have moved with the times.
A good example is wikipedia that (although not the perfect reference) refers to "Some digital file formats record a DPI value, or more commonly a PPI (pixels per inch) value, which is to be used when printing the image"
So both are used?
Also...."Pixels per inch (PPI) (or pixels per centimeter (PPCM)) is a measurement of the pixel density (resolution) of devices in various contexts: typically computer displays"
right..okay...and "PPCM can also describe the resolution, in pixels, of an image to be printed within a specified space. "
So it used to be one, then became another; also the latter has two definitions.

Well at least we all agree that it's just a ratio based upon the output of an image and arbitrary without that output dimension.
 
DizMatt said:
Well frankly I have to re-assess then... and I have played the 300 and 72 DPI (PPI whatever) game with someone recently with identical images. The software used said DPI.
PPI for me is always pixel density of a display. your phone screen has a PPI rating, have a look at the specs.
Click to expand...

OK I see what you mean. Yes that's a fair comment. You could use it in the exact same way as print size. Take the pixel resolution on each edge and divide by the horizontal and vertical width. That is what PPI does for prints. But really it's nit that relevant for that purpose and doesn't say anytthing about the screen in any way. On a tiny screen manufacturers like to baffle with numbers but these are fairly low resolution devices compared to large screens.


DizMatt said:
DPI has always been the actual output.

DPI used to be dots on the page printed but now this is expressed in PPI. okay, times have moved on. I'm pretty sure that it used to be DPI and that's still a legacy in most software packages which is where the confusion lies.
Your referenced article says "Adobe get it right with Photoshop and Lightroom but some software still incorrectly states dpi! No idea why! " Well, I think that's because the term was DPI and then Adobe have moved with the times.
Click to expand...


DPI is still dots placed on a print (in photography terms). It's disappointing that people get it wrong by referring to it as DPI. The two terms seem to have crossed paths and got stuck by those who don't understand it.

But PPI is still widely and correctly used. Allit does is determine the print size of your image though. The printer's dpi is a measure of the quality of the output and varies from device to device.

DizMatt said:
A good example is wikipedia that (although not the perfect reference) refers to "Some digital file formats record a DPI value, or more commonly a PPI (pixels per inch) value, which is to be used when printing the image"
So both are used?
Click to expand...
YTes they are but that doesn't make dpi corfrect and there's plenty of other writings around the web stating why.

DizMatt said:
Also...."Pixels per inch (PPI) (or pixels per centimeter (PPCM)) is a measurement of the pixel density (resolution) of devices in various contexts: typically computer displays"
Click to expand...

Yes I thinmk I could accept that however you would never base your decision to buy a monitor based on that. Pixel density tells you nothing about the display other than the number of pixels per inch. The monitor could be cheap rubbish still...... Same with phone screens ;)

DizMatt said:
right..okay...and "PPCM can also describe the resolution, in pixels, of an image to be printed within a specified space. "
So it used to be one, then became another; also the latter has two definitions.
Click to expand...

I have NEVER EVER heard anyone use PPCM as a measurte of pixel resolution......? Always ppi. (should never be dpi as that is wrong - just because it's used doesn't make it right lol

DizMatt said:
Well at least we all agree that it's just a ratio based upon the output of an image and arbitrary without that output dimension.
Click to expand...

Some interesting points thare though[/quote]
 
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I found the one guy who was in charge and knew what he was talking about, unlike his minions who were just robots " The computer says no!!" and anyway a picture says a thousand words;)
 
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