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by Bill Chambers on Tue Jan 11, 2022 12:09 pm
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Bill Chambers
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I have received an order for a large size print (70x48) and am having difficulty upsizing it to the needed size.

The image was taken with a GFX50s, native size for RAW file is 8256 x 6192 pixels and 112 MB.

I converted, cropped, and edited the RAW file in Capture One Pro 22 and exported it to PS as a TIF file sized at 6908 x 4795 pixels @ 360 ppi (19.3" x 13.3") and 189 MB.

I did additional editing in PS and saved as a TIF file sized at 6908 x 4795 pixels @ 360 ppi and 505.46 MB (unflattened & unsharpened).  For comparison later, I also saved a JPG of the image @ 1800 pixels long side>

To open the file in Gigapixel, I flattened it (189.56 MB) and saved it, then opened it in GP.
I upsized the file to 25,200 x 17280 pixels (70" x 48") @ 360 ppi.  

Here is where the problem arises.  The file is now too large to save as a TIF. Since GP cannot save as a PS Large Document, the only other options GP provides is JPG, PNG, and DGN.  So, I save as a PNG.

When I open the saved PNG file, I get 3 options – 1. Leave as is (Don’t Assign)  2. Assign working Gray: Gray Gamma 1.8 (It’s a B&W image).  3. Assign profile (of my choice)

I have opened the file using all three options (for option 3, I have chosen Gray Gamma 2.2, and sGray.  Regardless of which option I’ve chosen the image does NOT look the same as JPG I saved for comparison purposes.  

What am I doing wrong, and why isn’t the image looking the same as the comparison image I saved in my earlier step?  How can I correct this problem? Should I reduce the ppi from 240 vs. 360 in Gigapixel?
Please visit my web site, simply nature - Photographic Art by Bill Chambers
Bill Chambers
Milton, Florida
 

by signgrap on Tue Jan 11, 2022 2:51 pm
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Who is going to print the image? I assume that you can not print the image yourself. Is that correct? If it is, I'd ask the printer if he has a print RIP program and if he does I'm fairly sure he can do the upsizing. SantaFeJoe had the same issue recently and the printer handled it and Joe said it came out beautifully. He was starting with a smaller 35mm file I believe. Contact Joe
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by Bill Chambers on Tue Jan 11, 2022 3:38 pm
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signgrap wrote:Who is going to print the image?  I assume that you can not print the image yourself.  Is that correct?  If it is, I'd ask the printer if he has a print RIP program and if he does I'm fairly sure he can do the upsizing.   SantaFeJoe had the same issue recently and the printer handled it and Joe said it came out beautifully.  He was starting with a smaller 35mm file I believe.  Contact Joe
Thank you Dick.  I think I may have the issue solved.  I did what you suggested and contacted the printer (Artistic Photo Canvas) and Garrett suggested a process they use in these situations.  He suggested I save my native size image (approx 19x13) at a lower dpi setting (220 dpi) and then open it in Gigapixel and upsize to the needed size (70x48) @ 300 dpi. I was able to save it as a Tif using Zip mode.  When I opened it in PS, it looked the same (the tones) as the smaller jpg I made for comparison.  I applied sharpening and saved unflattened as a PS Large Document in case I need to change sharpening later, then flattened and re-saved as a Tif (zip) again.  I just tfr'ed it Artistic Photo Canvas and they will print a couple of 8x10 proofs of a couple small areas I specified so I can see how my sharpening looks at full size, as well as the general image.  Hopefully, it will work out well.

Thanks again for your kind assistance!
Please visit my web site, simply nature - Photographic Art by Bill Chambers
Bill Chambers
Milton, Florida
 

by E.J. Peiker on Tue Jan 11, 2022 5:38 pm
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Yup, always find out the details on the printer and then adjust the PPI to that. Also, in most cases, those printers print in 8 bit per color mode so changing the image from 16 bit to 8 bit will cut file size in half.
 

by Bill Chambers on Tue Jan 11, 2022 8:20 pm
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E.J. Peiker wrote:Yup, always find out the details on the printer and then adjust the PPI to that.  Also, in most cases, those printers print in 8 bit per color mode so changing the image from 16 bit to 8 bit will cut file size in half.
Thanks, E.J.,  Changing to 8 bits probably would have made a big difference.
Please visit my web site, simply nature - Photographic Art by Bill Chambers
Bill Chambers
Milton, Florida
 

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