How big can you go – from a 35 mm slide?

Every now and then I receive inquiries that are worth mentioning on this blog, because they tell stories of opportunities. Take this mail from Ben:

I’m thinking of having an image reproduced to fit inside a window frame inside my house… 68.5″ X 34.125″. I’m wondering on what film format it was shot and if the actual image is a bit wider than what we see to get the right aspect ratio and keep most of the water.

Ben.

The photo in question is this photo of Moraine Lake in the Rocky Mountains (excellent choice by the way):


Mark Zanzig/zettpress

This was shot on Fuji Sensia 100 slide film, a 35 mm film that was back then (in 2003) somewhat affordable while still giving precise colors with little visible grain. I have done good prints from this material up to 30″ x 20″. This is an area 473 times the size of the original. Wow.

But could the same material be sufficient for 68″ x 35″, which is about four times as large?

Ben’s inquiry made me wonder what this means in terms of dpi required. If we assume 200 dpi for the print (300 dpi would be better, but let’s be realistic), then the image would need a size of 13600 x 7000 pixels (95 Megapixels). Which is completely, totally, unmistakenly out of the question for a 35 mm slide. Why? Because 13600 pixels need to come from 1.378″ of raw film, which in turn means an optical scan resolution of about 9800 dpi.

Sure, there are scanners out there that produce 9800 dpi scans, but typically by using interpolation. And then the question remains whether the slide film material actually has that resolution (I doubt it). So even if you could do that scan technically, you’d probably end up with a grainy image.

But I see an opportunity for professional landscape photographers here: extend your business into panorama shots! Think of using a high end camera, e.g. a Canon 1ds mark III, and then stitch the images together! From four or five shots at 21 MP you can easily create such huge image files. And then sell them to customers like Ben. Or do poster prints and sell them in an online shop.

Want more photos? At Zanzig.com you will find more photos of Moraine Lake and West Canada.

2 Responses to “How big can you go – from a 35 mm slide?”

  1. Dietmar says:

    Hm. For such a large poster do we really need 200 dpi when printing it? I mean you would look at it from quite a distance most of the time anyway, right? Same like at the movies…

    – Dietmar

  2. Mark Zanzig says:

    I also think that 200 dpi is still luxury (and 300 dpi is out-of-the-question), but this was what Ben wanted. In a follow-up mail he mentioned that he thought of a “150 MB TIFF” image – which is a file 10200 X 5250 pixels at 150 dpi resolution. To create that size from a 35 mm slide is still ambitious. Anyway, I just wanted to make a case for large panorama shots. :-)