# Preparing to export for large format printing



## Ry_ (May 3, 2013)

Hi

I've tried reading up on this topic and found a lot of information, but nothing which makes things much clearer so I was hoping someone here might be able to assist.

Basically, I've created a panorama in Lightroom of the dimensions 6719px x 2240px. I've been asked to supply a 7 foot (approx 2.136m) print for indoor viewing and need to prepare my image for print.

The way I've used the Export dialog for small prints, e.g. 4 x 6", I specify dimensions, then specify 300dpi, no output sharpening, and the results come out great. The resulting files' pixel dimensions are reduced and I have a file to send to the lab.

With this latest image, my first thoughts were, specify the dimensions (2.136m x etc), set ppi to 300, then export.

Assuming 'Don't enlarge' is not ticked, the pixel dimensions increases. If It isn't ticked, the pixel dimensions stays the same.

I can't seem to leave the ppi blank so that it exports at it's native resolution.

I know ppi importance changes with viewing distance etc, but assuming this is going to be indoors and the viewer is going to be a metre or two away, and also that it needs to be roughly about 7' (2.136m) on it's long edge. Can someone help me optimise my settings so I can send this to the printer?

Thank you very much, much appreciated!

Ryan


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## wilderw (May 3, 2013)

At 300 dpi the longest dimension of your photo is 22.4". You cannot get to 7' with that image unless you print at a very low dpi 80 (poor quality) or you rescale your image up in size (which will also affect print quality). No free lunch here.


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## Mark Sirota (May 3, 2013)

Welcome to Lightroom Forums.

If you check "don't enlarge" and your size constraints are larger than the image, it's exporting at its native resolution. The PPI setting is irrelevant in this case.

But as wilderw says, at that size, you're going to want some rescaling. I don't think I'd go all the way to 300 PPI -- people aren't going to stand that close to a 7' print, most likely.  I'd probably go with about 180.

Why do you specify no output sharpening? Are you sanding to a lab which sharpens for you? If you're sending to a lab that's smart enough to handle that, I'd ask them how to prepare the file. If not, I think you're going to want some output sharpening for this.


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## Ry_ (May 4, 2013)

Thanks for the replies guys.

I didn't apply output sharpening at first because I sharpened my image in Develop and thought that would be fine, probably due to ignorance I thought applying output sharpening would then interfere with the earlier sharpening. I've checked it now to presumably compensate for the rescaling?

I just tried exporting my image from Lightroom. Original image size was 6719px x 2240px to 

TIFF
AdobeRGB (1998)
Compression: None
16 bits/component
Resize to fit: Long Edge 213.60cm
Resolution 300ppi
Don't Enlarge: not ticked
Output sharpening: Glossy: High (probably going to be on lustre paper, and I've read that glossy to matte will come out better than matte to glossy, so I went with the safe option)

The result from this was 25228 x 8409px at approx 1.27Gb, in Photoshop info, it says it's 300dpi.

So presumably, that's a file ready for print?

I then tried exporting at 180dpi, all other variables the same.

The result from this is 15137 x 5046px at approx 458.3Mb, in Photoshop file info, it says it's 180dpi.

Viewing the two side by side on screen at the smaller file's actual size, the smaller file looks better or sharper, presumably because of less interpolation.

So from these two images, can someone please (as patiently as possible, lol) help me determine or help me calculate how to determine which one to give to the lab, where the desired result is the higher quality print? In my ignorance I thought whichever looked right at 100% on a monitor was the one to go with, but now (thinking) I understand it better, I know that the 100% on monitor doesn't equate to 100% in real life?

Thanks again very much for the assistance!


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## Jim Wilde (May 4, 2013)

If you have a locally-attached printer, why not make a 1:1 crop of a small section of the panorama that has lots of detail, export once at 300dpi and again at 180dpi, print them and stick them to a wall....stand back a metre or two and compare.


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## Ry_ (May 4, 2013)

I haven't got a locally-attached printer unfortunately. 

Not that it'll help at all, but if anyone's curious, this is the image I'm working with:
http://www.flickr.com/photos/byry/8689473450/in/photostream/lightbox/


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## Pideja (Jan 11, 2017)

Just curious, did you get to do the test suggested by Jim Wilde?


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## Replytoken (Jan 12, 2017)

Pierre Desjardins said:


> Just curious, did you get to do the test suggested by Jim Wilde?


You are aware that this thread is almost four years old?

--Ken


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