Raw-jpeg file sizes for Alamy

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Doog

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Dougie
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Having a read through the requirements for submitting to Alamy, I notice they are looking for file sizes of 24MB. Now considering my D90 produces (had a look) file sizes in the region of 9-11MB and subsequent reduction when saving as Jpeg, do I need to upsize (new jargon to me) images to 24MB. It says the D90 is a suitable camera and I'm a bit surprised at the gap between what I'm getting and what they require. Am I doing something wrong in-camera to be getting such small file sizes? I'd be grateful if you can help me understand this.
 
The 24Meg is the uncompressed size that is shown in Photoshop, not the size of the file on disk.
 
you will probably need to upsize the file too. There have been a few threads on it in here in the past, try looking at Genuine Fractals.
 
The resize if required can be done easily in Photoshop...

Code: 
var SizeOfFile = prompt("Please Enter Size In Megabytes",24)
if (SizeOfFile > 0) resizeToMB( SizeOfFile ); 

function resizeToMB( size_in_MB ) { 
  var current_units = preferences.rulerUnits; 
  preferences.rulerUnits = Units.PIXELS; 
  var width_pixels = activeDocument.width; 
  var height_pixels = activeDocument.height; 
  var channel_count = activeDocument.channels.length; 
  var final_size = ( 1024 * 1024 * size_in_MB ) / channel_count; 
  var image_bytes = width_pixels * height_pixels; 
  var image_scale = Math.sqrt( final_size/ image_bytes ); 
  var final_width = width_pixels * image_scale; 
  var final_height = height_pixels * image_scale; 
  var final_dpi = activeDocument.resolution; 
  if ( image_scale > 1 ) { 
    activeDocument.resizeImage( final_width, final_height, final_dpi, ResampleMethod.BICUBICSMOOTHER ); 
} else { 
    activeDocument.resizeImage( final_width, final_height, final_dpi, ResampleMethod.BICUBICSHARPER ); 
} 
  preferences.rulerUnits = current_units; 
}
 
Craikeybaby said:
you will probably need to upsize the file too. There have been a few threads on it in here in the past, try looking at Genuine Fractals.
Click to expand...
Thanks I will:)
Paul MR said:
The resize if required can be done easily in Photoshop...

Code: 
var SizeOfFile = prompt("Please Enter Size In Megabytes",24)
if (SizeOfFile > 0) resizeToMB( SizeOfFile ); 

function resizeToMB( size_in_MB ) { 
  var current_units = preferences.rulerUnits; 
  preferences.rulerUnits = Units.PIXELS; 
  var width_pixels = activeDocument.width; 
  var height_pixels = activeDocument.height; 
  var channel_count = activeDocument.channels.length; 
  var final_size = ( 1024 * 1024 * size_in_MB ) / channel_count; 
  var image_bytes = width_pixels * height_pixels; 
  var image_scale = Math.sqrt( final_size/ image_bytes ); 
  var final_width = width_pixels * image_scale; 
  var final_height = height_pixels * image_scale; 
  var final_dpi = activeDocument.resolution; 
  if ( image_scale > 1 ) { 
    activeDocument.resizeImage( final_width, final_height, final_dpi, ResampleMethod.BICUBICSMOOTHER ); 
} else { 
    activeDocument.resizeImage( final_width, final_height, final_dpi, ResampleMethod.BICUBICSHARPER ); 
} 
  preferences.rulerUnits = current_units; 
}
Click to expand...

I won't pretend I know what that means and up till now I still haven't used photoshop, but my son has just showed me how that code works, so thanks.:thumbs:
 
One of the questions I should have asked is why? Why do they require such big files, ie. 24MB when I suspect most SLRs produce much less than this? Why can't they just except the file as is and let whomever is using it interpolate?
 
You don't need to upsize I don't think. If it is considered a suitable camera then the largest size jpg or a RAW file jpegged at 100% (ie minimum compression) should be suitable.

I've sent 14mp and 16mp straight off camera jpgs before now so I'd expect the 12mp ones of the D90 to be ok. JPGs can vary massively in size depending on content anyway so jpg size isn't always the best guide. I'm also fairly certain the alamy guide says not to upsize.

It would be much easier if they mentioned a minimum resolution in pixels rather than whatever it would work out as a TIFF. It's strange.
 
What it says:

Submission guidelines

We need:

Images from at least a 6 megapixel DSLR or more. See here for: Recommended digital camera list
JPEG’s saved at a high quality setting (i.e. Photoshop level 10 or above).
Alpha-numeric file names ending in .jpg.
RGB files, not single channel greyscale or CMYK.
Uncompressed file sizes of more than 24MB. This means you should make your JPEG file from an 8 bit TIFF file that is at least 24MB. If you have a camera that is capable of producing an uncompressed 8 bit file of over 24MB then leave it that size.

This is the bit that's confusing me. It seems to be saying two different things here or am I misunderstanding what this means?:shrug::bang:
 
From a 6MP camera you will need to interpolate, however if an image straight out of your camera is more than 5000px on the long side you should be OK.

Or if you want to be sure just convert it to an 8bit tiff and look at the file size.
 
No need to upsize at all. Infact I though it said it wouldnt accept upsacled images. Load your picture into PS and then at the bottom on the left it will have the actual uncompressed file size.
Ive uploaded files from a D200 and D90 to Alamy with no problems. Just exported them as full size, full res JPGs out of lightroom.
 
The do accept upscaled images, as if your images don't meet the size requirements they tell you up upscale them.
 
Craikeybaby said:
The do accept upscaled images, as if your images don't meet the size requirements they tell you up upscale them.
Click to expand...

Yeah you are right.

Do not crop your images excessively - after cropping, your file should still have an uncompressed file size at least 17MB at 8 bit.

If necessary, interpolate (upsize) the file to 24MB using a specialist, professional software package. If you have a camera that is capable of producing an uncompressed 8 bit file size of over 24MB then leave it that size.
We recommend Abobe Photoshop although other software is acceptable. If using Photoshop version 7 or higher select the bicubic option. We advise that you do not use “step” or incremental interpolation.
Click to expand...
 
I found this on the Alamy forum which clears it up no end:thumbs:


Our required file size for submitting Jpegs seems to cause an incomprehensible amount of confusion with a high volume of photographers. Put simply, we are flabbergasted as to how many times we are asked, daily, of what format and size of images we require!

Let’s set the record straight right now. First and foremost, yes, we want you to send Jpegs. No, we don’t want you to send Tiffs.

The reason for this is that we provide our clients with Jpegs to download, not Tiffs. It’s been industry standard to work like this for a long time now and even in the days when we required you to send us Tiffs, we converted them to Jpeg for the clients. Yes we know Jpeg is a lossy format, but to the naked eye, there is no visible difference between a high quality Jpeg and a Tiff file. The client can simply download the Jpeg, save it as a Tiff, and work away on it saving as many times as they like without loss in quality. It’s really that simple!
Now that’s out of the way let’s move onto file size. Jpeg is a compressed file format. The compressed file size (size on disk) varies with picture content and should generally be ignored, as long as it’s no bigger than 25MB, which is our upper limit for Jpeg size. What’s important is the uncompressed (opened) file size. The opened file must be at least 24MB at 8 bit to get through our quality control. Typically a 24MB 8 bit Tiff file will be between 2MB and 5MB as a Jpeg if your image was shot digitally. Film scans will be larger. This is because Jpeg “sees” film grain as image detail and compresses it too. Remember, we do not want a Jpeg 24MB in size as that would be ridiculously large when uncompressed (opened)!
One thing you don’t want to do is work on your images whilst they are in Jpeg form, repeatedly saving as you go along. Saving a Jpeg as a Jpeg is pretty much a no no, as you are recompressing an already compressed file.

Now there are various ways of doing this, but an ideal workflow example for creating the required file size would be:

* Convert your image into an 8 bit Tiff file (save as, Tiff)
* In an image editing program such as Photoshop, upsize the image to a minimum of 24MB (if you need to).
* Make any alterations as needed, inspect the image carefully at 100%
* At the very last step save your image as a Jpeg and send us that Jpeg. Remember, the Jpeg is the compressed size so this will typically be between 2MB-5MB

There are many digital cameras on the market that produce native uncompressed file sizes above 24MB so you will not need to do the above for those. The same goes for film scans.
Remember to also inspect your images carefully in accordance with our submission guidelines, found here:

http://www.alamy.com/stock-photography-guide.asp

Alamy
 
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