Sorry, @
raptik01 and @
MrToM, but, but I have a big worry.
While I have not seen the image in question, I doubt your passport office will accept a digital image manipulated in the way MrToM suggested if for no other reason that, at least in the USA, there is always a final inspection of the image by a human in addition to the software which performs a initial check of some of the numerical requirements.
1) @
raptik01 - I presume you are following rules such as these:
Technical Requirements
- File type: Jpg or Jpeg
- File size: Greater than 500kb and less than 10MB
- Dimensions: Minimum 900 pixels wide x 1200 pixels high -- maximum 4500 pixels wide x 6000 pixels high
- Aspect Ratio: 4:3 (Width:Height ratio)
These come from the New Zealand passport office:
https://www.passports.govt.nz/Electronic-photo-standards
Are these the rules that you are attempting to follow? If not, @
raptik01, could you please provide a link to the actual rules you are attempting to follow.
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2) @
MrToM - As far as I know, the JPG/JPEG file standard has never supported 16 bit per channel images, and, to this day, still doesn't. Photoshop will convert a 16 bpc image to 8 bit when you do a "Save As" into the JPG format. See this Adobe blog help file:
http://blogs.adobe.com/jkost/2010/07/saving_16_bit_images_as_jpeg.html
If you still don't believe this, just do a test yourself. You can can certainly save TIFFs and many other formats as 16 bpc images, but not JPGs, and that is the only file format NZ accepts. BTW, if you first convert the 8 bpc starting image to 16 bpc, and then re-save it as a JPG, this operation has an almost imperceptible effect on file size. Just to give you the benefit of the doubt, I just did this experiment myself.
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3) Exactly which IPTC or EXIF field do you suggest ( @
MrToM), or did you try ( @
raptik01) stuffing with useless metadata to go from tens of kb all the way up to a half meg? That's increasing the file size by about 30x. I ask because the IPTC (both core and extensions) and EXIF standards effectively have limits on the size of some fields, and they are not very large. In addition, many fields can not be repeated:
http://www.iptc.org/std/photometadata/specification/IPTC-PhotoMetadata
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4) I strongly suspect that the 12 kb image you want to artificially inflate to reach the half-meg file size requirement either has pixel dimensions that are under the stated minimum (900x1200 px), and it likely was saved with such a low JPG quality factor as to be unacceptable to the passport office.
As a test, I took a standard headshot from Wikipedia Commons, resized and cropped it to meet the minimum NZ pixel dimension requirements, and then tried various combinations of JPG quality factor and image blur, but always kept the pixel dimensions at the minimum acceptable values. The result was that even with a quality factor of zero, the lowest possible quality in PS, and artificially blurring the image to the point where it clearly wouldn't be acceptable to any passport office, I could never get the image smaller than 34 kb, ie, about 3x your file size. I've attached the 34 kb version below. This is why I strongly suspect your image doesn't meet the minimum pixel dimensions.
So, @
raptik01, how did you determine that the pixel dimensions met their specifications?
If you would care to share the image in question with us, then, instead of speaking in the abstract, we will be happy to check it for you.
HTH,
Tom M
PS - I really hope I am wrong, for example, because the requirements for pixel dimensions are much less stringent than I assumed, but no matter what country's passport rules you are following, 12 kb of real data sounds ludicrously small for a passport photo.
