Unprocessed RAW v JPEG print test

RAW is based on Tiff so why should you save it as Tiff and keep a RAW it only doubles the amount of space you need

Good idea, If I scan anything I always save it as a tiff. Print it and then pack it into a Zip. Documents can compress by 99%

Stefan, The idea of not printing from Raw is that you can use other programs to do the printing, such as Desktop Publishing progs.

shim

My logic would be to keep the original as it is, be it a RAW or JPEG file, and when it has been altered to make an A3 image for printing to save the new version as a TIFF.

Ironically, fotoLibra have now started converting all their TIFFs to JPEGs and are now asking for JPEG submissions as that is what most of their clients want.

In reality, there is not much that a top quality JPEG image is not perfectly good for. Like all of these things, the arguments tend to become over-stated.

I notice that in the discussion people have mentioned 100% and 200% crops; what is meant by this please?

RAW is camera specific, TIF is generic. Digital archivists (e.g. the Archaeological Data Service) will insist on TIF. Being a belt and braces person I tend to keep multiple versions of anything remotely important!

Cheers, Kris.

If I have taken a photo, usually I would post the whole thing:
[IMG]http://i156.photobucket.com/albums/t5/Prieni/_RDP4341pu.jpg[/IMG]

Now there is something special I want to convey (e.g. some minor faults with the picture that are only seen when enlarged). So I set the zoom in my photo processing software to 100% (that means that one pixel of the photo is shown on one pixel of the monitor). Then I cut out a portion of the original photo and post it. This means that one pixel of the photo will be shown on one pixel of your monitor.
Like so (the lower left corner of the photo from above):
[IMG]http://i156.photobucket.com/albums/t5/Prieni/_RDP4341crop.jpg[/IMG]
This is the 100% crop.
We do that in order not to post the whole photo in it's original resolution (which would be an alternative) but to show the "fine structure" of the photo without using too much memory (and therefore bandwidth).

Hope that made it a bit clearer,
Prieni

I think RAW contains more information than TIFF, so, as long as you have enough storage space, it makes sense to keep the RAW in case you ever want to re-process the image from scratch.

Re converting to TIFF for printing: It's interesting that ProAm Imaging - a professional print service - only ask for JPEGs, and only at "level 8". They claim you won't see any difference on the print with higher quality files.

RAW stores information in a different way. Essentially RAW data consists of the light values of every cell on the sensor (essentially they are grey values).
The RAW file will probably store the configuration of the Bayer filter as well so that the RAW converter can convert and interpolate the light values to construct coloured pixels.

I stand corrected...
Many of the RAW files are indeed extensions on the TIFF standard as can be found on Wikipedia: http://en.wikipedia.org/wiki/Raw_image

File contents

Raw files contain, by necessity, the information required to produce a viewable image from the camera's sensor data. Although there is no standard raw file format, the structure of raw files often follow a common pattern, that is:

* a short file header which typically contains the byte-ordering of the file, a file identifier and an offset into the main file data
* camera sensor metadata which is required to interpret the sensor image data. This includes the size of the sensor, the attributes of the CFA and its color profile
* image metadata which is required for inclusion in any generated JPEG file. These include the exposure settings and other EXIF data
* an image thumbnail
* optionally a reduced size image in JPEG format, this can be used for previewing the image
* the sensor image data

Many raw file formats (including 3FR (Hasselblad), DCR, K25, KDC(Kodak), CR2 (Canon), ERF (Epson), MEF (Mamiya), MOS (Leaf), NEF (Nikon), ORF (Olympus), PEF (Pentax), RAW, RW2 (Panasonic) and ARW, SRF, SR2 (Sony)) are based on the TIFF file format.[3] These files may deviate from the TIFF standard in a number of ways, including: the use of a non-standard file header, the inclusion of additional image tags and the encryption of some of the tagged data.

The Adobe digital negative format is an extension of the TIFF 6.0 format.

....But that doesn't mean a TIFF generated from a RAW will contain all the original info, or that your RAW program will treat it in the same way and be able to do as much with it.

Silkypix, for example, has certain functions that are greyed out when you open a TIFF or JPEG instead of a RAW file.

My understanding is that when shooting in RAW, the RAW file is the equivalent to the film negative, i.e. containing the information as seen by the sensor with no processing applied.

Certainly, the RAW file should be saved as is, and copies made in other formats.

A TIFF file is lossless, so it certainly contains all the information to reassemble the image.

TIFF is lossless in the sense of not using lossy compression, but that does not mean it contains everything from the RAW file. An image can be fully reassembled from it, but you can't necessarily do all the re-processing that you could with the RAW file.

There are various formats for TIFF as well, with some containing more data than others.

A TIFF is fine if you are are happy with your processing, but keep the RAW if you think you might ever want to process the image from scratch again to make a different image.

Pete, do you have any software which can sharpen selectively? I actually prefer the unprocessed background
I would say the lens was a Tamron 70-300, am I right?

Ashley, I still use JPGs most of the time - life's too short. If I have a corker of an image or one with a high dynamic range, I might dig out the Raw and have a play, always saving as TIFF.

I don't have software that can sharpen selectively. Interesting idea about keeping the background soft. I think my sharpening might have been too harsh for the foreground anyway.

Yes that's the purple-fringing Tamron 70-300.

With Silkypix, it's just as easy to process a RAW file as it is a JPEG, so I just shoot RAW for everything. I usually want to do something to each picture.