# Exporting photos for printing at specific file size



## Tommy999 (Sep 23, 2012)

Help,

I urgently need to save (export some images for printing latter)  they have asked for 1 to 3mgs , but i have been told 300 pixels per inch is the best resolution 
but the images are coming out as jpegs in export as 12 MG files -
How can i export to a 3 mg file size at best resolution ?

many thanks 

Also - cant work out how to make this a new post 

ta
Tommy


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## Replytoken (Sep 23, 2012)

Tommy999 said:


> Help,
> 
> I urgently need to save (export some images for printing latter)  they have asked for 1 to 3mgs , but i have been told 300 pixels per inch is the best resolution
> but the images are coming out as jpegs in export as 12 MG files -
> ...



Hi Tommy,

Welcome to the forum.  300 ppi is a common standard for printing a quality image.  Bbut, there are two other pieces of information that you need before taking action.  First, what is the pixel dimensions of your image that you are planning to export?  Second, what size will you be printing your image?  Once you have this information, it will be easier to work with you on determining the output file's resolution and jpeg compression settings.

--Ken


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## Tony Jay (Sep 23, 2012)

Ken is starting to chip away at the real issue now.

What an ideal PPI is, is somewhat open to conjecture.
It also depends somewhat on the printer.
You have an Epson Pro 4900 so lets concentrate on that one. (
We won't mention Canon and HP printers.)

Some relatively recent work done by Jeff Schewe has uncovered some interesting facts.
Printing at input native resolution (for the printer) is better than printing at other resolutions.
Edges tend to print cleaner and sharper.
Your Epson input native resolution is 360 PPI.
(BTW this has NOTHING to do with resolution of ink dots placed on the print - that is orders of magnitude higher.)

Jeff's recommendation is if the native resolution of your image is less than 360 PPI uprez the image on printing to 360 PPI.
If your native resolution is greater than 360 PPI uprez the resolution to 720 PPI.
(If memory serves the printer driver on your 4900 should give you that option.)

How does one know the 'native resolution' of the image.
Native resolution of the image is dynamic and depends how large you wish to print.

With an uncropped image from my Canon 5D III, if I decide to print at A2 size, with margins set @ 0.5 in, then Lightroom reports the resolution of the image as being 257 PPI.
(To confirm native resolution unselect 'Print Resolution' in the the 'Print Job' subpanel that forms part of the R panel in the Print module. Glancing at the top of the image it should report dimensions, in either cm or inches, @ xxx PPI.)
In this case in Lightroom I would ask the Print module to print @ 360 PPI.
This would be confirmed at the printer driver level.

If I decide to print A4 size with the same margins of 0.5 in, then Lightroom reports the resolution of the image to be 539 PPI.
In this instance I would ask my Epson to print this a 720 PPI.

Now the real issue is how big could a particular image be printed?
There is no one correct answer because it really depends on the content of the image.
Another factor is one called 'viewing distance'.
Another important variable is the print medium (a high-gloss or semi-gloss paper, size for size, will show much more fine detail than a matte paper or canvas).

An image with a lot of fine detail would be more limited in in uprezzing than an image that is much less detailed.
Viewing distance is also important. Billboards you view from the freeway can be printed with circles of colours the size of apples. Up close and personal you would not be able to distinguish what you were looking at. Viewed from far away the billboard looks brilliant.

I know many professional photographers who print at file resolutions of 180 PPI and uprez to 360 with no issues particularly if they printing on matte papers or to canvas.

The bottom line is to experiment with different sorts of images at different print sizes (hence resolution), and different print media, and see how they look.
If the large prints look sharp and appropriately detailed to you then well and good.
If you see the largest prints look a bit mushy then check a smaller size print, and so on, until the print looks good.
Also look at the print from different distances - remember larger prints are better viewed from a distance.

This is a subjective process - ask others to help you and see what they think.
With time one learns how far to push a prticular sort of image.
Printing has a lot of science in it but ultimately it is a bit of a black art because a print is subject to aesthetic subjectivity.

Regards

Tony Jay


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## Victoria Bampton (Sep 23, 2012)

Welcome Tommy!  I've split this thread off for you - the new thread is this one, at http://www.lightroomqueen.com/commu...ing-photos-for-printing-at-specific-file-size


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## erro (Sep 23, 2012)

My article on "Image size, resolution, PPI, DPI etc." perhaps may help you:

http://erro.se/artiklar/Bildstorlek/#english


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## Replytoken (Sep 23, 2012)

Tony Jay said:


> It also depends somewhat on the printer.
> You have an Epson Pro 4900 so lets concentrate on that one. (
> We won't mention Canon and HP printers.)



Thank you for the more detailed response about PPI and printing, Tony Jay.  But, I was confused about one thing - I am not clear where you have determined that the OP has an Epson Pro 4900?  Were you just using this as an example?  I know that my past Epson printer's have printed at multiples of 360ppi, but I also know that other brands run at multiples of 300ppi.  It would be helpful it the OP knew specifically if 300ppi was required, or if he just thought that was a good benchmark.

--Ken


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## Tony Jay (Sep 24, 2012)

I could have sworn I saw a reference in the OP to an Epson 4900. (In fact this post has been split by the moderators.)
That why I concentrated on Epson.
With Canon and HP the native input resolution is 300 PPI as you are alluding to.
Otherwise the same principles apply.

Regards

Tony Jay


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