Upsizing to Large Prints - start with 300 dpi or 240 dpi file?

I have mixed feelings of how my photos look blown up to 24" x 36".

Currently, I shoot RAW and process in Adobe Lightroom which turns out a file at 300 dpi that's roughly 7.5" x 10.5". I then use OnOne Genuine Fractals software to enlarge the file to 24" x 36" at 300 dpi. Genuine Fractals is considered one of the best software for doing this.

However, I find the results mixed. Please advise if changing to the following processes would be better:

- Still proess to 7.5" x 10.5" but upsize to 24" x 36" at 240 dpi with Genuine Fractals; or
- Process at 10.5x15", the image size if outputted at 240 dpi in Lightroom and then upsize to 24" x 36" at 240 dpi with Genuine Fractals.

Anyone know whether I would get better results with changing to above processes?

Files or images cannot be measured in inches. They have no physical reality. Only prints have inches. Likewise, dpi is meaningless because it depends on the existence of a print. Since you are not making a print until after the image has gone through GF, you have to stop thinking about the export from LR in those terms and start thinking about the number of pixels, the only property that the image has. An image that is 2400 x 2400 pixels and tagged with 240 dpi so that it defaults to a 10x10 print and an image that is 2400 x 2400 pixels and tagged as 300 dpi so it defaults to a 8x8 print, are exactly the same image. The different dpi tags are meaningless.

For that reason I started to write that the two alternatives quoted above are the same. Then I looked again at the numbers and saw that they represent two different crops (neither of which is appropriate for 24x36 paper, btw). The first is 2250 x3150 and the second is 2520 x 3600. Are you asking which crop will be better printed large? Obviously the bigger one. Equally obviously, the best thing you can do for your large prints is to get closer and crop less. But if you are limited by access to your subject or lens selection, you will have to accept that even GF will not retain maximum quality at the 3x resampling needed for 24x36 inches at 300 dpi. (Although I would expect it to be very good at normal viewing distance, which for a 24x36 would be about 4 feet.).

So to recap, the only property of the export from LR that is important is the pixel dimensions. As to whether you would be better off taking it up with GF to 5760 x 8640 (240 dpi) or 7200 X 10800 (300 dpi) would depend on the printer. If it is being printed on a machine like a Frontier whose RIP will resize to 300 dpi, you might be best off continuing to let GF do all the resampling. OTOH, I have had beautiful results as low as 200 dpi from a Durst Lambda which has a variable scan and will give much the same results anywhere from 200 to 400 dpi.

Some time ago "Amateur Photographer" ran a serious lab test using all the top end resizing programmes. After a lot of exhaustive work and printing massive enlargements the conclusion was that none of them did any good at all.

The unresized images printed at the same physical size looked identical to the uprezzed ones, in some software the uprezzed ones actually looked worse.

I've found on my R2880 I can print at 180ppi without noticing any deterioration in the quality, even with my nose against the paper. I imagine if I viewed an image from 6 feet or more I could go dramatically bigger.

I never resize. My image files are sent to the printer at whatever ppi they happen to be and the printer driver sorts it out. It seems to be very good at doing that.

ppi is irrelevant, only number of pixels counts. I use photoshop, it works fine. If the lab will do it, let them.

Yes, Epson, Canon, etc. are not fools. Nor are Fuji, Durst and other makers of commercial printers. The resampling routines used by home drivers and RIPs are of very high quality today, although this was not always so. Tests I did with my old Epson 1290 many years ago showed much better detail when I did my own resizing to 360 ppi, but today with the 1900 I see very little difference between 180, 240 or 360 ppi. Nevertheless, printing from LR and therefore not saving a huge tif, I will let LR crank it up to 360 ppi (although I also export a tif that size just to see if I'm satisfied with LR's output sharpening and to soft-proof it and then delete it.) I suppose it all comes down to how much of a control freak you are, what (bloated) opinion you have of your own ability and judgement, and what your time is worth.

tzalman wrote in post #9625581
Files or images cannot be measured in inches. They have no physical reality. Only prints have inches. Likewise, dpi is meaningless because it depends on the existence of a print. Since you are not making a print until after the image has gone through GF, you have to stop thinking about the export from LR in those terms and start thinking about the number of pixels, the only property that the image has. An image that is 2400 x 2400 pixels and tagged with 240 dpi so that it defaults to a 10x10 print and an image that is 2400 x 2400 pixels and tagged as 300 dpi so it defaults to a 8x8 print, are exactly the same image. The different dpi tags are meaningless.

For that reason I started to write that the two alternatives quoted above are the same. Then I looked again at the numbers and saw that they represent two different crops (neither of which is appropriate for 24x36 paper, btw). The first is 2250 x3150 and the second is 2520 x 3600. Are you asking which crop will be better printed large? Obviously the bigger one. Equally obviously, the best thing you can do for your large prints is to get closer and crop less. But if you are limited by access to your subject or lens selection, you will have to accept that even GF will not retain maximum quality at the 3x resampling needed for 24x36 inches at 300 dpi. (Although I would expect it to be very good at normal viewing distance, which for a 24x36 would be about 4 feet.).

So to recap, the only property of the export from LR that is important is the pixel dimensions. As to whether you would be better off taking it up with GF to 5760 x 8640 (240 dpi) or 7200 X 10800 (300 dpi) would depend on the printer. If it is being printed on a machine like a Frontier whose RIP will resize to 300 dpi, you might be best off continuing to let GF do all the resampling. OTOH, I have had beautiful results as low as 200 dpi from a Durst Lambda which has a variable scan and will give much the same results anywhere from 200 to 400 dpi.

Thanks for everyone's answers. I think I got it.

Basically, however, you slice it up, you start with the same amount of pixels. And from what people are saying, they don't see a huge difference or any between 180, 200 dpi and 300 dpi on today's printers. So it sounds like I should process to go ahead and generate as large a print I can, lowering the dpi output.

Rock Photo Star wrote in post #9628118
Thanks for everyone's answers. I think I got it.

Basically, however, you slice it up, you start with the same amount of pixels. And from what people are saying, they don't see a huge difference or any between 180, 200 dpi and 300 dpi on today's printers. So it sounds like I should process to go ahead and generate as large a print I can, lowering the dpi output.

Or just totally ignore dpi, crop the image to the right aspect ratio, then print using the 'Maximum Size' template in LR with 'Zoom to Fill' and 'Rotate to fit' selected. That should give you the highest dpi possible for that image printed at that size on that printer.