# How many dpi (or ppi) would you print a 1,5x3m (59"x118") back lit poster at?



## Forceflow (Aug 31, 2012)

Hi!

Not sure if this is the right place, but couldn't find any subforum that really seemed to fit my question.

I just got a request from a friend who wants me to take a landscape photograph for her that will be hung up in her winery. It will be printed on semi transparent paper mounted behind a plexiglass wall and then back lit. She mentioned that people should be able to get fairly close to it and should still be able to make out details then. I currently have a 7d and figured for this I would need at least 150dpi which would result in 12 photographs. (24 if you take into consideration that images need to overlap and that you should have some room on all sides for final composition) If I go to 300dpi (which I think would be overkill) we're talking about 44 (or rather 88) photographs. (Unless my calculations are wrong of course)

Does anybody have experience with prints this large (and printed on transparent paper) Is 150dpi reasonable, way too little or too much after all because you'll never get this much detail on non-photo paper anyways?


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## lola (Aug 31, 2012)

Here's an excellent read to answer all your questions & more!

http://www.cambridgeincolour.com/tutorials/digital-photo-enlargement.htm#


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## woollybear (Aug 31, 2012)

> Here's an excellent read to answer all your questions & more!
> 
> http://www.cambridgeincolour.com/tutorials/digital-photo-enlargement.htm#



The article was excellent (I saved it, BTW), but I don't think it really addresses his question.


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## lola (Aug 31, 2012)

woollybear said:


> > Here's an excellent read to answer all your questions & more!
> >
> > http://www.cambridgeincolour.com/tutorials/digital-photo-enlargement.htm#
> 
> ...



Well, yeah maybe not directly but, the calculator near to the end of the article should definitely prove useful and the concept of blowing up the images in post-production might save the original poster from taking 10-20-30-whatever photos and stitching 'em together.


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## Plato the Wise (Aug 31, 2012)

You are referring to a Duratrans. 

Most high end imaging labs will print a lightjet print on semi opaque material for back-lighting. A lightjet large format print is usually printed at 150 pixels per inch. But, it may not be necessary to tile an image. You may be able to res-up the image using photoshop.

You can actually do a test by cropping a portion to 8x10 and having the lab run it on the light to see if the quality is suitable.


Here is a good link:

http://www.duggal.com/connect/possibilities/photographic-printing/what-are-lightboxes-and-what-kind-does-duggal-offer


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