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Author Topic: JPEGs to 48MB files - is it possible?  (Read 13705 times)
judyc
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« on: February 05, 2007, 06:25:29 AM »
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Hi, I have a number of images that I would like to submit to agencies/photograph libraries as my first submission.  Only recently, have I saved files as TIFFs or RAW, the majority are as 300 dpi JPEGs.  

Can I generate a 48MB file from a JPEG file?  If so, how would I do this either in Photoshop or would I need another program?  Any detailed advice you could give me (I'm a bit of a techno-phobe) would be much appreciated.
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Tim Gray
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« Reply #1 on: February 05, 2007, 07:43:32 AM »
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Well, you can, but that's not going to solve your stock problem since they will likely be able to tell, particularly if you have to up-size.   What they are really after is an original uncompressed file of a certain resolution.

In any event you can get a big file simply by saving in 16bit tif.  If that's not big enough up-rez a higher resolution, but again, the file is only going to be as good as the file you started with.
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LoisWakeman
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« Reply #2 on: February 05, 2007, 07:55:29 AM »
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Well, you can, but that's not going to solve your stock problem since they will likely be able to tell, particularly if you have to up-size.   What they are really after is an original uncompressed file of a certain resolution.
That may be true of some agencies - but Alamy specifically tell you to upres 5Mb digital files for example.
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LoisWakeman
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« Reply #3 on: February 05, 2007, 07:58:31 AM »
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Can I generate a 48MB file from a JPEG file?  If so, how would I do this either in Photoshop or would I need another program?  Any detailed advice you could give me (I'm a bit of a techno-phobe) would be much appreciated.
If you have a PC, you could try Qimage Pro (from http://www.ddisoftware.com) which is very good for upressing and has many other uses too; otherwise, there are several well-known PS techniques for stepwise upressing that you should be able to find by Googling.
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redwoodtwig
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« Reply #4 on: September 30, 2007, 11:06:04 AM »
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If you have a PC, you could try Qimage Pro (from http://www.ddisoftware.com) which is very good for upressing and has many other uses too; otherwise, there are several well-known PS techniques for stepwise upressing that you should be able to find by Googling.
[a href=\"index.php?act=findpost&pid=99270\"][{POST_SNAPBACK}][/a]

I've seen this kind of discussion in other places.  What I don't understand is what the agency thinks they are gaining by requiring 48mb files.  If they required 10,000x10,000 resolution, for example, they could count on getting what they are looking for, but file size by itself has very little to do with resolution and quality.

I recently sold an image on line through smugmug to a friend who wanted a 30x40 inch print.  I laboriously upsized by using the size menu and repeatedly hitting it with 105% upsizing.  But the file got to be too big for them to handle, and when I asked about it they said to simply send the original, that the lab that does the printing has very expensive and high quality software that would take care of it.

Which leaves me still wondering what the agency thinks they are gaining by asking for such large file sizes.
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Brandon Smith
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jjj
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« Reply #5 on: September 30, 2007, 06:50:53 PM »
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I've seen this kind of discussion in other places.  What I don't understand is what the agency thinks they are gaining by requiring 48mb files.
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It's because they have no idea about resolution, file size and quality and what difference these attibutes make to image quality.  It's a hangover from film scan file sizes I believe. My 35mm scans are 70MB, but does that then mean they are they better than files from, say a 1DsII, whose files are not as large.
Besides it all depends on output size anyway as to the file size needed for the job.
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Henry Goh
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« Reply #6 on: October 22, 2007, 11:08:47 PM »
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Hi, I have a number of images that I would like to submit to agencies/photograph libraries as my first submission.  Only recently, have I saved files as TIFFs or RAW, the majority are as 300 dpi JPEGs. 

Can I generate a 48MB file from a JPEG file?  If so, how would I do this either in Photoshop or would I need another program?  Any detailed advice you could give me (I'm a bit of a techno-phobe) would be much appreciated.
[a href=\"index.php?act=findpost&pid=99258\"][{POST_SNAPBACK}][/a]

Not sure if you have Alamy in mind but if so, I think you may have misunderstood their requirements.

48Mb does not refer to JPG file.  It refers to an 8-bit TIF file.  When you save that file at best quality JPG, you would get around 5 or 6Mb.  Alamy accepts that JPG file.  JPEG compresses the data so that 48Mb TIF file will be compressed when saved as JPG.  Hope this helps.

BTW, with say a 6Mp file, you need to upsize to get 48Mb.  You can now easily do this in PS CS3 in one go.  There is little benefit to use Genuine Fractals or Qimage or Photozoom Pro since Photoshop's algorithm is now very good.
« Last Edit: October 22, 2007, 11:11:23 PM by Henry Goh » Logged
Diapositivo
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« Reply #7 on: October 24, 2007, 07:34:24 AM »
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I would like to integrate the post above by Henry Goh.

The 48 MB requirement is tipycal of Alamy so I also suppose it's Alamy we are talking about.

This 48 MB thing "uncompressed" has caused much misunderstanding and is actually an ambiguous way to describe size image. You might save your JPEGs as TIFFs and they will have a dimension in Photoshop (let's say 48 MB or so) then you go to Windows Explorer and you see they are smaller (evidently consensus on what a MB is is still to come).

So the basic rule in Alamy is this:
You can send JPEG file, provided that the pixel count of the actual image (once opened in Photoshop in 8-bit depth) is at least 16 millions. So you just multiply the height in pixels for the width in pixels, and if the number you obtain is > 16,000,000 then the image satisfies Alamy's minimum size requirement.

(Note that I say "million pixels" to avoid the use of the expression "megapixels" which would probably raise the question whether a megapixel is 1,000,000 pixels or 1024 x 1024 pixels).

Your image can be bigger than this. I normally send images around 55 MB (scanned).

If the dimension in 8-bit format is less than 16 millions pixels than you upsize it just to be above 16 millions pixels. As you are interpolating there is no need to go beyond the minimum requirement.

So your normal workflow from your JPEGs would be.

a) Open them in Photoshop;
 Convert them to 16-bit TIFFs;
c) Do all the corrections you want to apply to the file;
d) Check pixel dimensions;
d2) If pixel dimension is not OK, scale up;
e) Convert to 8 bit file;
f) Save as JPEG maximum quality.

This JPEG file is what you upload to Alamy. Its maximum dimension must be 20 MB you don't have a problem of exceeding maximum dimension if you start from a DSLR.

Your JPEGs images might fail Quality Control if there are JPEGs artifacts visible in the image (patchworks of squares 8 bit size for instance, or diagonal lines being jagged, you can spot those problems by inspecting the image at "actual pixel size"). Conversion to JPEG format which is made "in camera" might not lead to results acceptable to Alamy (also depending on your camera settings).

As far as I can grasp from Alamy forum, images captured with JPEG "in camera" are not much beloved by Quality Control. Your mileage may obviously vary.

Cheers
Fabrizio
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