Mike Chaney's Tech Corner

Hello,
I hope somebody here in the forum knows the answer.
Qimage was not able to open a 8bit tiff file 38000 pixels wide so I decided to crop it and save 2 files, with 30000 and 30001 pixels. The one with 30000 pixels opens fine but the one with 30001 pixel shows the typical "image read error" and fails to open.
I wonder if anybody has any experience with files above the 30000 limit.
Thanks,
Armando

Hi Armando,
Image read error is more to do with the format of the image rather than its size so I would look again how it was created.
You say the image was 38000 pixels wide but what about the other dimension? Please tell us what that is.
I dont follow that you have split a36000 pixel wid image into 30000 + 30001px - why is the total bigger?

There will be a limit on image size depending on your system resources and QU will warn you if that is the case. You can determine what this is by going to Help, click Analyze Current Settings with the Shift key held down too.
See attached screen shot for a typical result on a W7-64 PC.
To calculate the MB size of an image (not file size!)
MPixel width x MPixel height x3 (for RGB)

Terry

Hello Terry,
Thanks for the quick reply.
Images are from a 4000dpi scan of 4x10s.
Memory is not an issue. I'm running x64 with 8gb so the info shows 2gb, 800mb, 2gb.
Qimage pro version 2010.207

Two images:
image#1 --> 30000 pixels wide
image#2 --> 30001 pixels wide (one extra pixel)

Both images are 1.X gb in size (<2GB) saved as TIFF 8bits, in PS CS5

Image#1 opens fine. Image#2 shows the typical "image read error".

Thanks again,
Armando

Hi Armando,
Don't think you have been abandoned  ;D Fred & I are doing some tests, the results of which we do not understand as yet. It could be one for Mike C to answer.
Terry

Armondo-

I have a question. What are you doing a 4000 dpi scan of? I can't imagine anything that would benefit from that high a dpi scan. Are you really getting any more useful data at that dpi than you would at 1000 or 2000 dpi? Surely, if you are scanning 4x10 prints, there's no useful data at that resolution. If you are scanning negatives, I'm still not sure 4000 gives you more real resolution than 2000. What film will do that res?

Jeff J.

Thanks Terry & Fred. I'll keep an eye on the thread.

Hi Jeff,
Almost all color ISO 100 in the market would easily get details on the 4000 dpi, (I'm familiar with Ektar 100, E100G, Provia, Velvia). The bottle neck is most likely to be in the lens, where low dispersion glass (like the apo-sironar-s series) can do the job.
For a 40"X100" print is not a big loss but at >60" wide I could use a lot of details left behind.
Thanks again,
Armando

Mike is on the job as always.
He has made some tweaks to the code which will (using my SHIFT ANALYZE readings of 2.0 gigabytes) now allow a read of a TIF just over 1 gigabyte.
In subsequent tests, if you were to resave the TIF using the option of LZW compression, Qimage Ultimate will be able to handle 1.7 gig Tif images.
The new release of Qimage Ultimate should be out in a day or two at most.

Thanks for being so patient, Armando

By the way, if one side of the image in question was 30000 pixels, what was the other dimension?

Fred

The original file was 38000x15000. I even tried with a cutoffs 30001x1 and 30000x1

That works out to just over 1.7 gigabytes filesize.

Too big!

Thanks,
Fred