How can I save my RAW file at the highest quality possible?

AJSJones wrote in post #11642728
Just to clear up a little of the mud here
jpeg and TIFF are storage formats for RGB files. Once they are opened and displayed they are both RGB files. Your printer will be sent the RGB file which is converted into information for the inks in the printer.

Ahem. Yes, you're right.

I meant to say that all companies that take your file and print it on their machines require JPEG. Well, maybe not all of them, but ...

-js

There was a program called Genuine Fractals that used complex algorithms to upsize images that may be useful to you if you need more, it's been renamed now Perfect Resize. http://www.ononesoftwa​re.com/products/perfec​t-resize/

tienbien wrote in post #11641885
I'm shooting on a Canon EOS 20D taking 8.2MP RAW photos. I'm using Photoshop CS3 RAW software to edit the pictures, and I want to save them as high of quality as I can so that they can be blown up and put on a wall. I need them to be as big as possible. I know I want to save them as a TIFF file, definitely not a JPEG, but the question is, how exactly can I make sure they're the highest quality?

When I'm in the RAW software, I click the "Save Image" button and I can save it as a TIFF, but I don't have a lot of options for settings. Here's an example of a file I saved as a JPEG and as a TIFF. They have the exact same dimensions, but the file size of the TIFF is larger:

3504 x 2336 pixels, 14.6 x 9.733 inches, 240 pixels/inch
JPEG File Size: 3.1 MB
TIFF File Size: 23.4 MB

What I want to know is, is this as high as it will go, or is there something I can do to make it even higher quality? Can I save it with larger dimensions, or do I even need to? Is the TIFF file simply enough information to make, say, a 30 x 45 print? What about a 50 x 75?

Thanks in advance for any help you can give me.

Tiff is either uncompressed or lossless compression as far as I am aware - so pretty much "no loss".
On that note though, a highest level JPEG image is just as good, and possibly easier to handle for printing UNLESS you need more than 8bit colour depth.

(PS: My JPEGs can be similar in size to RAW files on the lowest compression setting if I have some fine grain in them)

Jim_T wrote in post #11643083
If you want maximum information saved to disk, save your images as 32 Bit TIFF.

Will that help when the best cameras are "only" 14bit color? You can't stretch extra color info that is not there.

Andy R wrote in post #11641989
its all about DPI (dots per inch) open your file in cs3, go under image, then image size, and then unclick resample image, this will put a bracket on the sides and resolution, now click on resolution and change it, this will change the size, 350dpi is the best your printer can do (there might be higher ones but not that i have ever used) and you can lower it to say 200, this will make the image bigger but your loosing dpi (quality), you can go as low as around 150 with the image still looking "ok"..........

tkbslc wrote in post #11642200
DPI means NOTHING in digital images. Your image only has dots, no inches, in a computer. You don't get inches until you print it on a certain size paper, and then you can work out the dots per inch............

Those two posts provide the definitive answers.

Something else to consider -- I do not know if you have found a printing service that can produce 50 X 75 inch prints on photo quality paper at a reasonable cost. There are also large format ink jet printers used by businesses to print size E drawings or for printing small signs and banners that use paper (or Mylar) rolls, but I am not sure about rolls of photo paper that wide.

When a photo is printed on plain paper, there will be a lot more blurring of individual ink dots compared to photo quality paper which means that sending a high DPI image to the printer using lower quality paper would be meaningless (and the printer driver might downsample to a lower resolution, discarding some of the data anyway). As far as DPI is concerned, with an extremely large print like you want, you could easily go to 100 or even 72 DPI without a problem even when printing on photo paper. It is not necessary to have the same resolution as a small print where the high resolution is necessary to keep fine details from blurring together. A very large print would not have that problem -- instead, the limiting factor would be the image pixel density at the displayed size. It would be worthwhile to find out beforehand what resolution the printer actually uses and consider scaling both the image and print size to not use a greater DPI density. I would prefer to do that in Photoshop where I have some control over the outcome rather than letting the printer RIP (raster image processor) do the resizing. As previously mentioned, scaling the print size has no effect on the actual image data since it is only an instruction to the printer that gives the size that you want. However, the printed results is greatly affected by the way that the printer handles the image data when converting RGB pixels to CMYK dots on paper.

Color profiling on such a printer might be an issue unless there are printers of that size designed for photo printing. I suspect that sRGB is the best colorspace that can be expected from a large format printer. Therefore, it probably is not worth saving the image in a large colorspace such as AdobeRGB. Also, saving the image at anything greater than 8 BPC is probably unnecessary, especially considering that printers only use eight-bit color data when converting RGB data to the printer's CMYK color profile.

I do not know if it makes any difference, but I prefer using the PSD format rather than TIF.

tkbslc wrote in post #11642200
...As for the original question, there are no parameters for quality with a TIFF file because it always saves at the same (high) quality. JPEG has variable compression so can balance file size and quality. If you have the drive space, TIFF is the best option.

Why not save the edited RAW? Isn't the RAW file the highest quality form of the image?

Tim S wrote in post #11647311
Why not save the edited RAW? Isn't the RAW file the highest quality form of the image?

I think you can say ironically not, as the quality of the final image depends on the RAW interpreter. Besides, not all RAW interpreters/converter​s read the same "stuff" - Canon's DPP uses Metadata and Adobe Bridge writes .xmp files.

On that note - RAW files technically aren't images either, they are sensor data, a collection of red/green/blue measurements.

Tim S wrote in post #11647311
Why not save the edited RAW? Isn't the RAW file the highest quality form of the image?

It depends why you are saving - saving to archive the image and/or print at home or saving to do something with it outside your home/office, like sending it to a print lab or offset press. Anything that leaves the boundries of your domain will need to be a rendered image.

I may be a day late with this but hopefully not a dollar short.

To the OP, a couple bits of advice:

First, talk to your lab and get clear specifics on their requirements and recommendations. Some will accept a tiff, so you could submit one if you prefer. You should know, though, that there will be no noticeable difference between a tiff and a full size/full quality jpeg -- jpeg conversions are quite good at keeping detail intact.

What your print lab may specify is a minimum ppi resulution, in which case you may need to resample the image. The printer will do the resampling otherwise.

For big prints, resampling can be an advantage to you anyway, because you can both get an idea of your image quality and you can apply some "output sharpening" at the resampled print size. How much of that you need will depend on the image, But again, your lab may apply effective sharpening, again a good reason to talk clearly and thoroughly with them.

Someone mentioned color space and that's another important bit of info to get from them -- they may handle aRGB images well or you may be best to convert to sRGB. They should be able to give you good advice there.

Then another bit of advice -- run a couple small crops through them as test prints -- crop your image to print an 8x10 at what would equate to the image printing at full size and cutting out an 8x10 section. View it at a reasonable distance, not with a magnifying glass!.

So you'll have some perspective here -- I have a bunch of prints on my walls that are 12x16 prints and 12x18 prints from several digital cameras ranging from 4MP sensors, to an 8MP 30D. I consider all the prints quite viewable (it helps to have a good original image) although, again, I don't look at them with a magnifying glass, although sometimes I do a little "pixel peeping".

Prints from my 30D are in fact quite crisp and sharp in the fine details.

There are some folks on here who actually run print shops and have reported excellent results of printing quite large, so if those images have good crisp IQ you should be in good shape.