How large a file can be printed?

[pico]

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I have a 2.37 GB file to print to 40" x 40".

 

The file is 38221 px x 38221 px. Way too large?

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By dead reckoning you seem to be printing at a density of about 1k pixels per inch which I'd like to see even in a smaller print. Depending on the printer, I'd aim for 280 or 300 or so.

 

The following thread might contain the answer to your question, I hope:

 

http://www.l-camera-forum.com/leica-forum/digital-post-processing-forum/115989-digital-printing-pixels-resolution-resampling.html#post1230246

 

(TL/DR )

[adan]

As to absolute size, that probably depends whether the printer software/driver has size limits that will choke on that many pixels.

 

Keep in mind that printers have a "native" output resolution, and will downsize or upsize an image on the fly to match that value. About 240-360 for inkjet printers. Send them 1000 ppi images, and they will downrez to the native range anyway.

 

(Photographic printers like a Lightjet also print at 300 ppi - they sometimes advertise "4000 dpi" but that is compared to printing-press halftone dots, like newspapers or magazines).

 

So your "38821" pixels will be printed as about "14400" max., no matter what you send the printer.

 

I usually get my cleanest, sharpest prints by downrezzing them myself to the printers' range, and then sharpening. If you want to preserve the original full detail for the archives - make a duplicate file at the lower resolution for printing.

[01af]

Photographic printers like a Lightjet also print at 300 ppi—they sometimes advertise "4000 dpi" but that is compared to printing-press halftone dots ...

That's not "compared" to anything. Instead, ppi and dpi simply are two different things. From the printer's point of view, pixels are what comes in and dots are what goes out. Each pixel from the input will translate to many dots in the output.

 

Regarding the original question—for a print size of 40" × 40", before sending your file to the printer better downsize it (or rather, a copy thereof) to 12,000 × 12,000 pixels for a 300 ppi printer or to 14,400 × 14,400 pixels for a 360 ppi printer (Epson).

[atournas]

A rule of thumb is this (all distances in inches):

 

1. Decide on the distance of viewing the print; call that distance D.

2. Call P the largest side of your sensor in pixels; e.g., M9's is P = 5270 pixels.

3. The largest acceptable print you can make will have the larger side S in inches:

 

S = 0.00029 X D X P.

 

Or, half that value to get an even denser print.

 

For example, for a print to be viewed from a distance of 30 inches, the largest acceptable print from an M9 image will be S = 0.00029 X 30 X 5270 = 45-inch wide print.

 

This formula is a summary of an analysis to be found in http://www.l-camera-forum.com/leica-forum/leica-m9-forum/130720-leica-m8-m8-2-m9-m9p-2.html

 

Paul

[pico]

Thank you, Andy. You addressed exactly my concerns.

 

I will try some downrezzing right now.

[tobey bilek]

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I print M9 raw at 240 at my lab which uses a Lambda printer on photo paper. Sharpen is 25 amount and .7 pix in ACR. That is too much to allow further sharpening and the files come out looking like details on money, yet not over sharpened.

 

Inkjets with matt paper or gloss are different still on sharpening. The Nikons require more except for the D800e which has no AA filter. People say 300 ppi except for Epson which is 360. I dislike prints from inkjets so I send out.

 

This whole thing is intertwined with medium, glossy, matt, book, or photopaper and sharpening. You need to experiment. You can print a section of the file to 4x6 to simulate a large print. Then view at appropriate distance. There are too many variables to just take internet advice.