? about RAW

[justleesa]

OK I finally tried taking a few more pictures in RAW mode with my 5D and noticed something

After adjusting the picture and converting it to a jpeg I see that the picture has a resolution of 350dpi and is something like 8x12"

If I look at the pictures taken with the same camera in jpeg mode the resolution is 72dpi and the size is around 60x40"

Both RAW and JPEG modes were set to the largest res.

I always wondered ....I read that the best res for a printed pic is 300dpi (+), why do the cameras in jpeg mode take the pictures only with 72dpi? Converting a jpeg pic later to 300dpi isn't the same as getting it with 350dpi straight out of the camera, is it?

 

[Tortuga Roja]

Both pix you describe are really the same size (except that you rounded off a little I guess). What really counts is pixel dimensions. Remember that DPI is a printing term of how many dots (pixels) will be printed in one inch. More inches printed = less dots per inch.

notice that 8"x350(dpi) and 40"x72(dpi) are nearly identical (with out your rounding off they would be exactly the same. 2840 (or 2880 depend on which one you rounded) is the pixel dimension of the short side of your image.

It's kinda confusing until you get the concept. It's best to only think about pixel dimensions (how many pixels by how many pixels) until you are ready to print. Then look at the size you want print and you will detemine if your DPI is high enuf for the printer.

IOW, if you printed either of the images at the same size, you would have the same rez.

This is kinda hard to explain with words. Much easier with sketches.

 

[Chris Bangs]

I have no clue as to why some cameras produce 72 dpi Jpeg files. A 300 dpi image would be better for printing and having to resize and save a Jpeg = lost quality.

With many RAW converters, you can choose the resolution of the converted file. the size stated in inches will change based on this choice. higher dpi = smaller size. for me this is nonsense, since I convert to Tiff and resize the image based on my printing requirements and when I am finished futzing with the Image I will save it both in Tiff and Jpeg, the Jpeg is only used for printing.

300 Dpi used to be the best choice for home printing but now with the higher resolution printers higher Dpi settings may improve the output.

 

[Larry C]

Sometimes you might also want a smaller picture with high resolution, or you might want to make the whole file smaller for e-mail or posting on a limited forum. If you have photoshop (my 7 will do it, I don't know if elements will) you can resize the picture in inches or cm and change the resolution in mp at the same time. Just go to "image", "file size" and alter the dimensions and resolution, then "save as" whatever format (jpeg, tiff, ps, etc.) that you want to store the file as.

 

[Footslogger]

Sometimes you might also want a smaller picture with high resolution, or you might want to make the whole file smaller for e-mail or posting on a limited forum. If you have photoshop (my 7 will do it, I don't know if elements will) you can resize the picture in inches or cm and change the resolution in mp at the same time. Just go to "image", "file size" and alter the dimensions and resolution, then "save as" whatever format (jpeg, tiff, ps, etc.) that you want to store the file as.

=======================================
Downsizing is especially handy for website uploads.

'Slogger

 

[Tortuga Roja]

It just doesn't matter what the dpi of the file is. If you print either one of the images Justleesa mentions at 8x12, you will have the same resolution print.

 

[RonFrank]

OK I finally tried taking a few more pictures in RAW mode with my 5D and noticed something

After adjusting the picture and converting it to a jpeg I see that the picture has a resolution of 350dpi and is something like 8x12"

If I look at the pictures taken with the same camera in jpeg mode the resolution is 72dpi and the size is around 60x40"

Both RAW and JPEG modes were set to the largest res.

I always wondered ....I read that the best res for a printed pic is 300dpi (+), why do the cameras in jpeg mode take the pictures only with 72dpi? Converting a jpeg pic later to 300dpi isn't the same as getting it with 350dpi straight out of the camera, is it?

What software RU using? Photoshop for example generally displays PPI NOT DPI as it should be PPI.

The first important thing to recognize is that PPI and DPI are different terms even if they get used in an interchangable manner. PPI is what the camera is outputting. DPI is the number of dots per inch for a given output device.

Most inkjet printers have several output qualities. In general they look something like:

normal: 300 x 300 or 320 x 320 dpi
high quality: 600 x 600 or 720 x 720 dpi, 1440 x 720
photo quality: 1200 x 1200, 1440 x 1440 dpi, 2880 x 1440 and up

The myth is that one needs the PPI to be equal to the DPI to get a good print. In fact the general rule of thumb is that the PPI should be about 1/2 to 1/4 that of the DPI to get a good print. Generally a PPI of between 240 and 300 is enough to produce high quality output on any printer.

Another thing I've read is that keeping the PPI in even multiples of the DPI is a good idea. So if you are printing at 1440 DPI, size the image to 288 PPI, not 300 PPI.

There is an additional factor here to make things more difficult, and that is LPI. The necessary LPI is based on the printer capabilities, and the paper used. LPI (lines per inch) is based on the hardware used, so you need to look at the printer you are using to determine what LPI is appropriate.

Here is a chart to help determine approapriate sizes for printing:

http://www.tasi.ac.uk/resources/pixel.html

Is this all confusing... yes.. Do you need to understand this to get the most out of your printing... yes.... BUT you can get by without full knowledge.

Is printing an ART.. .YES!! Factor in the even more difficult side of printing.. color space, and device calibration, and then image adjustment, and subjective color balance, and you end up with PRINTING=ART

In the digital world of inexpensive PnS camera's, and technologies like PMI print matching, and inkjet printers it's easy to believe that photography, and printing is not all that difficult.. I mean a child can do it right? The reality is that those who really understand what they are doing are the in demand professionals that will make a living doing this type of thing regardless of how LUCKY some people get allowing technology to do it all for them.

 

[Chris Bangs]

Ron, Well stated!

Now that I am back on Guam I will once again be printing some images. I need to get back up to speed on the latest techniques and/or software/hardware for color calibration.

Currently I am using the Epson pigment based printers and I plan to soon get one of the latest ones due to ink improvements

please provide whatever info and links thst you think will make printing less painful!

BTW, you have some nice stuff in your gallery!

 

[RonFrank]

Ron, Well stated!

Now that I am back on Guam I will once again be printing some images. I need to get back up to speed on the latest techniques and/or software/hardware for color calibration.

Currently I am using the Epson pigment based printers and I plan to soon get one of the latest ones due to ink improvements

please provide whatever info and links thst you think will make printing less painful!

BTW, you have some nice stuff in your gallery!

Thanks, they were and remain my first UW photo's... sigh.. living in CO has some drawbacks :11doh:

I use a 2200. The major improvements in the Epson pigment inks are in two areas. First the K3 inks which are now in the 4800, 7800, 9800, R2400 printers include a new light light black ink. This is really only going to benifit you if you do a lot of B&W fine art prints. The R2400 is likely the printer one would choose for professional results up to 13" wide. The 4500 jumps the price to about $2000 MSRP, and gains one a 17" path.

The second improvement is for those that want high gloss in a pigment archival based ink. The one criticism of the P2200 is that it can bronze a bit when printing gloss depending upon the subject. My solution is that I use Premium Luster paper, and the prints are gorgous. If you like a true high gloss print Epson now makes the R1800 which uses a pigment based ink designed for high gloss paper, and it's a bit less expensive vs. the R2400 as well (not sure why).

None of these improvements have prompted me to run out and purchase a new printer, the 2200 is working fine for me even if it's OLD technology. The archival quality and print quality were good enough for me 2 years ago, and that remains true today.

There are really only two names I can think of in budget minded calibation tools and software that is Monaco, and Colorvision (Spyder). If you want to just calibrate the monitor, then Spyder offers a solution for under $100. If you want to profile your monitor, then the more expensive monaco and Colorvision solutions are around $200. If you want to profile your printer, things start getting a LOT more expensive. However colorvision makes a product called PrintFIX that does printer profiles for around $250 (that does NOT include monitor calibration software or hardware).

I've read good things about the PrintFIX printer profiler, but you may choose to pay for a professional profile (there are services that do this) or you can just live without one (I don't have a custom printer profiler, and find I don't need one). It WILL make printing easier, I guess it depends a lot upon if you are able to get the results you want without one. Epson profiles are excellent for their respective papers. If you are looking to constantly change papers, then a printer profiler is a good solution. If you tend to stick with one paper, then I'd just work on getting that dialed in, and not worry too much about a printer profiler.

 

[stiebs]

I was going to answer this, but I see it has already been well covered by others. DPI means nothing until you go to print it. And for most home users, you don't even need to worry about it then - just specify what size you want the end product, and the software figures it out for you.

When I get my photos printed professionally, its on a 20"x32" sheet at 250dpi. But all I need to do is create a 8000x5000 pixel image in PS. Doesn't matter if I save the TIFF as 72 dpi, because the printer prints it at 250dpi regardless.