Need to read/write IPTC in TIF/TIFF

[ChuckE]

Re: "reopening and saving repeatedly"

Please note, that is not quite what I said. I was not re-opening the same image. You may already understand that, but that is not what your phraseology indicates.

At each step I was opening the most recent saved image, a whole new generation, once further removed from the original. Here are the unique color counts. (By the way, all files being JPG, have the ability to have up to 16.7 million colors since there is capability in the JPG to have 24bits of color info per pixel. I have no where even close to that number of unique colors, of course. especially since there is only 3.15 M pixels to begin with in these photographs.)

Unique colors:
Original = 183523
1st gen = 174434
2nd gen = 173589
3rd gen = 173792
4th gen = 173620
5th gen = 173627
6th gen = 173580
7th gen = 173575
8th gen = 173586
9th gen = 173595
10th gen = 173589
11th gen = 167676 (this is where I saved, from the 10th, at a 100 quality level)
12th gen = 171041 (and now back to an 80 quality level)
13th gen = 171036
14th gen = 171035
15th gen = 171035

[Sam_Zen]

(OT indeed, but)
Thanks ChuckE, this is a very thorough investigation by a lot of effort.
According to the results, I'll have to re-evaluate my standard warnings about compressing the compressed.
Intuitively I already found the ~ 80 setting the right value for getting the same quality/filesize result.

[Mayuko]

After being pointedly reminded not to herd cats partaking in an off topic discussion, I continued to look for a solution to my problem described above. I found what appears to be a workable solution. Unfortunately, it does not involve IrfanView.

Microsoft has released a free plug-in to the Windows Explorer which allows the input and editing of IPTC information in TIFF (and other format) files. I have also confirmed the IPTC information within TIF format is preserved when converted into the easier to manage JPG by Photoshop CS2.

The plug-in in called Microsoft Photo Info. Version 1.0 was released in January 2007. Photo Info is free and can be found at the Microsoft website (use a search engine to find it).

My relatives now have the ability to circulate and add IPTC information within photos using a lossless format (TIFF) using a widely distributed platform (Windows). I note that PNG format is not supported.

I look forward to someday using IrfanView to support my projects. I do sincerely hope a comparable feature is added to IrfanView.

My thanks to this forum for allowing me the opportunity to engage the sentient members of this discussion. I hope this information is helpful to those who wander down this path someday.

Sayonora.

-M

[ChuckE]

Thanks Mayuko, for the lead to the free Microsoft tool. Actually I had downloaded it over 6 months ago, but never installed it. Your mention of it made me search for what I had.

For anybody else, here is a MS link:

http://www.microsoft.com/windowsxp/using/digitalphotography/prophoto/photoinfo.mspx

I have now tried the MS tool, and this starts a whole new set of descrepancies. I have found some tags named by IrfanView are not named identically by Microsoft.

I am not detailing those issues in this thread, that's not the point of this thread. So I'll start a new one ...

[Flit]

It's a lot about the principle, people need to understand about generational loss first of all, that goes equally for lossy audio like mp3.
Many don't and blindly hit all varieties of buttons resulting in a definite loss.

You can't know what kind of settings people have, what programs they use or what "you haven't heard of" purpose the image may have to serve someday.
It's okay to recommend .jpg on a per-case basis, but i think it's not okay to propagate "it doesn't matter" on just personal observations.

p.s: i think Mayuko made the right choice with .tiff for now

[matrixik]

Maybe someone still needs the good and free program to editing EXIF/IPTC/XMP so I recommend ExifTool (command-line application):

http://www.sno.phy.queensu.ca/~phil/exiftool/

And GUI:
ExifToolGUI:

http://freeweb.siol.net/hrastni3/

They even can add EXIF/IPTC/XMP to PNG but unfortunately I don't know program that can recognize that meta in PNG.