Which format to save your photos?

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The QCC
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Which format to save your photos?

#1 Post by The QCC » Mon Dec 29, 2014 1:54 am

A very quick comparison of four image formats.
TIFF, JPEG, BMP and PNG. The RAW format is missing because RAW files are well, raw and not viewable without conversion to another format.
The forum is limited to 1024 pixels, so precise comparison is not possible. But zoom in and see if you can detect the differences.
The camera is a generic 5MP eyepiece unit mounted in the viewing tube of an AJ Optiks SPL polarizing microscope. The objective used is 5x. The subject a thin section of Porphyritic Rhyolite. The snapshots were saved with no compression or maximum quality.
All images are post processed in my usual manner in Adobe Lightroom. The white/black balance is set and sharpened with the mask set for narrow edges only.

My observations of the original sized images (2592 x 1944) are there is very little or no difference between the JPEG, BMP, and PNG formats. The TIFF image shows improvement in dynamic range and is the format of choice for large prints.
The file size for the BMP image (14.4MB) makes it a poor choice for archiving.

Your opinions may vary, but I can see no reason why the JPEG format at high quality cannot be the standard format for image capture with TIFF used for special jobs.

Yes, I do use the RAW format when shooting with a Canon camera and yes it is better than JPEG when heavy cropping and processing are required. I have the Canon set to take RAW + JPEG and 90% of the time I delete the RAW image.

A four image composite.
4ImageComp.jpg
This is the centre crop of the four image composite.
4ImageCrop.jpg

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Oliver
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Re: Which format to save your photos?

#2 Post by Oliver » Mon Dec 29, 2014 7:09 am

Hello,
JPG: lossy compression, image quality goes down when saved, but low image size and the loss of quality can be adjusted and in most cases not noticable. Used for the web due to small size, it is the standard for photography and can/should be used
TIFF: loss less compression, used when processing the images, which are then saved (=no quality loss) to be further processed later.
PNG: loss less compression, but optimized for graphics which are published on the web.
BMP: not compressed at all, large file size, has only historical relevancy. Used by Windows for many tasks, when CPUs were not powerful - compression/decompression time was still relevant.
Raw: company specific, useful when shooting at extremes and when large color depth necessary.

There should be no difference in image quality between TIFF, BMP and PNG, not even in theory. All of them use 24bit colors and are lossless compression. Dynamic range is increased (significantly) when taking RAW images, but so is filesize.

Generally the image quality provided by the microscope is the bottle neck and not so much the file format. I therefore would stay with JPG and only save as TIFF when you do Photoshop editing of the images (and then the final saving is JPG again for publishing). I would try different JPG compression levels to test the resulting image quality to find the one that still gives you acceptable results.

Greets, Oliver
Image Oliver Kim - http://www.microbehunter.com - Microscopes: Olympus CH40 - Olympus CH-A - Breukhoven BMS student microscope - Euromex stereo - uSCOPE MXII

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vasselle
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Re: Which format to save your photos?

#3 Post by vasselle » Sat Jan 10, 2015 8:09 pm

Bonjour
Avec ma camera Bresser MicroCam je capture mes photos au format TIFF et pour APN Canon PowerShot en mode RAW grâce a CHDK.
et je trouve que de capturé en mode RAW avec son APN permet de gagné en plage dynamique et ces beaucoup mieux après pour le poste traitement de ces photos.
Car si on capture directement en JPG on a a une plage dynamique moins importante et en plus ce n'est pas top pour faire du poste traitement après car le JPG ces 8 BITS.
Le JPG je m'en sert juste a la fin de ma chaîne photographique pour archiver mes photos, car je sert cas se stade je ne touche plus mes photos.
Car le JPG ce comporte comme une pellicule diapositive alors que le RAW comme un pellicule photo "film".
Bonne continuation et bonne observation.
Cordialement seb
Microscope Leitz Laborlux k
Boitier EOS 1200D + EOS 1100D

The QCC
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Re: Which format to save your photos?

#4 Post by The QCC » Sat Jan 10, 2015 10:45 pm

I agree with Vasselle.

JPEG is the very last format and only for archives that will NEVER be used again.
Sixty percent of my images are Postscript or Photoshop and archived with the 7Zip format.

The times when I use a commercial print house, the printer requires 16bit TIFF files or Adobe Acrobat 16bit PDF files.

Off line disk storage is inexpensive at approx. $150.00 for 3TB and no longer a reason to conserve space by saving everything as JPEGs.

If Lightroom is your image manager or you use the Adobe DNG converter you can now save your RAW files in a lossy format. Thus preserving the 14-16 bit RAW file depth.

I have placed 1:1 crops of a RAW file and the lossy DNG on my server.
You can download the ZIP file and compare the them. The files are in TIFF format.
The original RAW file is 15MB and the lossy DNG version 7.2MB. The TIFF crops are 1.3MB each.

JimT
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Re: Which format to save your photos?

#5 Post by JimT » Mon Jan 12, 2015 11:53 pm

I convert my RAW files to TIFF and save both (The good ones) as Tiff's.
Like QCC said, storage is so inexpensive it does not make sense to compress as JPEG's.
Lastly, every time you open and change a JPEG file you degrade the image further.

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gekko
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Re: Which format to save your photos?

#6 Post by gekko » Tue Jan 13, 2015 12:09 am

I set my camera to save as RAW, edit them in Elements (and save as .psd as I edit), then resize them for posting and save both as .psd and as .jpg which I upload. Not much different from you'all.

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75RR
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Re: Which format to save your photos?

#7 Post by 75RR » Sun Jan 18, 2015 8:14 pm

I stopped saving in RAW, files were just too large and I did not see an advantage.
Now I save as JPG, open in Camera RAW (possible with Adobe Bridge) for the first round of editing and save as TIFF.
Second round with Photoshop and the save as JPG again. Keep TIFF in case I want to go back and change something.
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

The QCC
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Re: Which format to save your photos?

#8 Post by The QCC » Sun Jan 18, 2015 9:00 pm

75RR:
One of the advantages of RAW files is the high bit depth with its greater depth of colours.
If you start with JPEG at maximum quality it is still an 8 bit image. Converting to TIFF in Photoshop and then back to JPEG is a Loss - Loss process.
Adobe Bridge with Camera RAW allows a much greater range of adjustments on a JPEG image, but you are still working with an 8 bit image.

If you save for maximum quality, your are definitely not saving space by saving in the TIFF format. Add adjustment layers in Photoshop and the TIFF file balloons like Microsoft Windows OS.
The image information below is from a Canon 5D MkII RAW file saved as compressed TIFF and JPEG at maximum quality.
HobbySandSGlue_LM5X_003_4x.CR2 25.1 MB
HobbySandSGlue_LM5X_003_4x.jpg 13.8 MB
HobbySandSGlue_LM5X_003_4x.tif 38.5 MB

The above assumes maximum quality for prints, presentations or publications.
If you view your images on the Web or on a computer monitor, then JPEG from start to finish is adequate.

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75RR
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Re: Which format to save your photos?

#9 Post by 75RR » Sun Jan 18, 2015 9:39 pm

QCC
I stack most of my images.
Each JPG saved by the camera is 2.3MB
Lets say I take a set of 10 on average of each subject.
Thing is I take several sets with different illumination – oblique/BF/DF and within those a couple of sets with different settings.
So could take 40/50 photos of a single subject, that is a lot of MB at 2.3, imagine in RAW.
I save the TIFF's in high quality (one original + one final one post processing) but the final JPG at 72pp
I have no plans to print images, nor can I see myself published/exhibiting anywhere.
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

chalshokhi
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Re: Which format to save your photos?

#10 Post by chalshokhi » Mon Feb 23, 2015 10:59 am

JPEG is the very last format and only for archives that will NEVER be used again. Sixty percent of my images are Postscript or Photoshop and archived with the 7Zip format.

The QCC
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Re: Which format to save your photos?

#11 Post by The QCC » Mon Feb 23, 2015 12:29 pm

I agree.
My capture format is RAW, processing is TIFF, printing is Postscript.
As my post processing programme is Lightroom, RAW is also my archive format.
Photos that were processed in Vue Esprit and Photoshop are saved in TIFF format.

Archival disk space is so inexpensive there is no need to archive in JPEG format.

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Re: Which format to save your photos?

#12 Post by gekko » Tue Feb 24, 2015 1:03 pm

One thing that I don't think was mentioned above is that, as far as I understand, images posted to the forum (or to be viewed on a computer monitor in general) should be in (converted to, if necessary) sRGB color space (they may look washed out in Adobe RGB because most[?) monitors cannot show the wider Adobe RGB color space.) I see a big difference on my monitor.

The QCC
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Re: Which format to save your photos?

#13 Post by The QCC » Tue Feb 24, 2015 2:16 pm

All RAW files must be converted to some other format if they will be viewed on a monitor. An unconverted RAW file looks almost black.
Most computer monitors can display 100% of the sRGB colour space and many new monitors can display 90-100% of the Adobe RGB colour space.

The colour space of choice for the web is sRGB. To show the image at its best on the web they would have to be converted to a format that supports the ICC profile sRGB.
Most web browser can view JPEG and TIFF images, but JPEG is preferred because of its size when compressed.

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