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Tuesday, October 23, 2012

Extend Your Range


Ordering Close Focus • Sign Here • JPEG Vs. JPEG • The Coolscan Dustup

Labels: How-ToColumnTech Tips
I use fine-point metallic ink pens, either silver or gold, because they don't fade and can be seen easily. Having metal flakes in the ink makes them permanent. Graphite pencils were used by many black-and-white photographers in the past and shouldn't fade, but they can smear. Pencil won't work on many inkjet papers. India ink also has been used, but I don't advise it; you're limited to black, and it will fade in time. I have several Ansel Adams prints signed with India ink, and the signatures are fading; fortunately, the prints are doing just fine.

Your prints are an expression of your art and you can sign where you want, as big as you want and with whatever you want. I would argue for consistency, however, especially if you're marketing widely. Your signature then becomes a recognizable "brand."

JPEG Vs. JPEG

Q If I take a photo in RAW, upload it to the computer, and without any processing, save it as a JPEG, and then take the exact same photo with the camera in "large fine JPEG" and upload it to the computer, will there be any differences in the two images—one where the computer processed the RAW file to JPEG and one where the camera processed the photo?
J. Berke
Via email


A There are a number of uncontrolled variables in your scenario, so we spent an hour or so trying to construct a test that would answer your question.

For the purposes of this test, it's important to disable as much as possible the default settings within the camera that will affect the JPEG. These range from file size (from a large fine JPEG, for example, down to a small JPEG), to in-camera processing options such as sharpening, contrast control and saturation, as well as automatic noise suppression. Some of these processing modes are optional, and thus controllable. The largest file size available was chosen for the JPEG, and all of the in-camera processing for the JPEG capture was set to zero.

To eliminate any possible variation in the capture, we captured both the RAW and JPEG images in one click. In some recent DSLRs, you can capture a RAW image and a JPEG image at the same time; the camera either can save both captures to a single CF card or can place the RAW file on the CF card and the JPEG on a second card, either a CF or SD card. We used a Canon EOS 5D Mark III and a convenient subject (the landscape outside my studio) containing both bright, sunny areas and shade.

We then downloaded both images to Photoshop. The "fine JPEG" and the RAW capture reflect the same number of megapixels (22), but when downloaded, the RAW capture, being a 16-bit file, is twice the size of the JPEG capture, an 8-bit file. This means the RAW file contains much more information at the outset, a mathematical fact that's visually confirmed when the two unprocessed images are compared side by side in the computer. The RAW capture has more detail than the JPEG in bright and dark areas of the image.

But when the unimproved RAW capture was compressed into a JPEG, and thus reduced to an 8-bit file, we found that the image initially captured as a JPEG was of slightly better quality. So even with all JPEG processing options set at zero, I still find the JPEG images have been "improved" as compared to RAW captures compressed to JPEG format. The noise suppression built into the camera is obviously at play here.

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