Saving Pictures in Tiff CMYK or RGB??

Saving Pictures in Tiff CMYK or RGB??

Post by WStoreyI » Thu, 25 Dec 2003 03:19:50



Hello,

I have recently learned that jpgs corrupt files.  So i opened psp6 and went
to convert all the files that i have in to Tiffs however it had an option
for RGB format or CMYK format.  My questions is which one do i use, my
printer (Epson Stylus Cx5400)uses cmyk color cartridges so i was thinking
that is what i should use and that i could convert them to rgb if i need to
use them for the web or anything.

Please tell me if this is the right assumption and if not what to do.

Thanks & Happy Holidays

WStoreyII

 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by Tom Thackre » Thu, 25 Dec 2003 03:29:35



Quote:> I have recently learned that jpgs corrupt files.  So i opened psp6 and
> went
> to convert all the files that i have in to Tiffs however it had an option
> for RGB format or CMYK format.  My questions is which one do i use, my
> printer (Epson Stylus Cx5400)uses cmyk color cartridges so i was thinking
> that is what i should use and that i could convert them to rgb if i need
> to
> use them for the web or anything.

> Please tell me if this is the right assumption and if not what to do.

First, since they're already jpeg, leave them as jpeg. The 'corruption' has
already happened. When you edit them you can save the edited copy as a tiff.

Second, save them as RGB. The jpegs are RGB and you will loose some
information in the conversion. Your printer will do the RGB->CMYK conversion
when you print.

--
Tom Thackrey
www.creative-light.com
tom (at) creative (dash) light (dot) com


 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by Mike Russel » Thu, 25 Dec 2003 03:31:43



> Hello,

> I have recently learned that jpgs corrupt files.  So i opened psp6
> and went to convert all the files that i have in to Tiffs however it
> had an option for RGB format or CMYK format.  My questions is which
> one do i use, my printer (Epson Stylus Cx5400)uses cmyk color
> cartridges so i was thinking that is what i should use and that i
> could convert them to rgb if i need to use them for the web or
> anything.

> Please tell me if this is the right assumption and if not what to do.

Save yourself some work.  Stick with RGB, since your printer driver takes
RGB input anyway.

And save yourself some work and stick with your jpgs for that matter.  Jpegs
will indeed lose quality, but only  each time you re-save in jpeg format.

Treat your original jpeg from the camera as if it were a negative, save your
edited image to another file, and avoid compressing the image more than one
additional time.  If you plan to edit the same image again, save in an
umcompressed format such as tiff or psd.

Above all, try these things out for yourself and see if you can see the
difference - trust your eyes over anything you read here, including anything
I say :-)
--

Mike Russell
www.curvemeister.com
www.geigy.2y.net

 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by Rowle » Thu, 25 Dec 2003 03:48:24


    "Above all, try these things out for yourself and see if you can see the
difference - trust your eyes over anything you read here, including anything I
say :-)"

I've noticed that there are a lot of very knowledgeable people in these groups,
along with a lot of people who think that they are knowledgeable - problem is
it's hard sometimes to tell the one from the other.

Martin



> > Hello,

> > I have recently learned that jpgs corrupt files.  So i opened psp6
> > and went to convert all the files that i have in to Tiffs however it
> > had an option for RGB format or CMYK format.  My questions is which
> > one do i use, my printer (Epson Stylus Cx5400)uses cmyk color
> > cartridges so i was thinking that is what i should use and that i
> > could convert them to rgb if i need to use them for the web or
> > anything.

> > Please tell me if this is the right assumption and if not what to do.

> Save yourself some work.  Stick with RGB, since your printer driver takes
> RGB input anyway.

> And save yourself some work and stick with your jpgs for that matter.  Jpegs
> will indeed lose quality, but only  each time you re-save in jpeg format.

> Treat your original jpeg from the camera as if it were a negative, save your
> edited image to another file, and avoid compressing the image more than one
> additional time.  If you plan to edit the same image again, save in an
> umcompressed format such as tiff or psd.

> Above all, try these things out for yourself and see if you can see the
> difference - trust your eyes over anything you read here, including anything
> I say :-)
> --

> Mike Russell
> www.curvemeister.com
> www.geigy.2y.net

 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by Taci » Thu, 25 Dec 2003 04:04:23


Quote:>I have recently learned that jpgs corrupt files.  So i opened psp6 and went
>to convert all the files that i have in to Tiffs...

That will not bring back the lost quality.

When you save a picture in PEG, you lose quality. It's gone forever; taking
that JPEG and turning it into a TIFF will not bring the quality back.

If you decide to change the picture later, then save it as a TIFF. Editing it
and saving as JPEG would lose more quality. But if the pictures are already
JPEG, the damage is already done.

Quote:>however it had an option
>for RGB format or CMYK format.

Inkjet printers use RGB, even though they have CMYK inks. The inkjet printer
CMYK isn't the same as offset printing CMYK; if you send CMYK data to a home
inkjet printer, the driver converts it to RGB, then back to the inkjet
printer's own variety of CMYK.

--
Rude T-shirts for a rude age: http://www.villaintees.com
Art, literature, shareware, polyamory, kink, and more:
http://www.xeromag.com/franklin.html

 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by Taci » Thu, 25 Dec 2003 05:56:13


Quote:>1. Where did you learn that jpg corrupts files? Nonsense.

I suspect the original poster meant that JPEG degrades image quality--which it
does.

Quote:>2. Your camera is sRGB, your video display is sRGB. All printers are CMYK.

The camera and video display are RGB. sRGB is a color space; it can be assigned
to an image for display on a device, or assigned to an image captured by a
device, but the camera and video display are not sRGB. sRGB is a definition of
a working color space, not a device.

Quote:>We used .tif in the old days because resolution was poor and "save as" jpg
>many times would degrade the image.

Save As in JPEG multiple times will still cause cumulative degredation. TIFF is
a good, universal format for uncompressed or losslessly compressed images; it
is not useful only for low-resolution images.

Quote:>Things have changed dramatically and unless you want to print very
>large (by large I mean more than 12 x 18) from a pro shop there is
>absolutely no advantage to save tif files over jpg.

JPEG is lossy. TIFF is not. You may not be able to see the loss personally, but
I can, and others can too.

JPEG is only useful if you are short on space, and file size is more important
than quality. In the day of $80 hard drives, if you are so short on space you
care more about file size than about quality, you need a bigger hard drive.

Quote:>The first point is, every time you "Save as" a jpg there is a little loss
>and artifacts introduced, so if you edit a picture and you Save as many
>time, there is some degradation with each Save as, but not with Save if
>you
>use Save to save your changes as you are editing

Incorrect. Saving a JPEG creates cumulative degredation. If you edit the image
and then Save, it does the same re-compression as if you had used Save As.

You can verify this for yourself easily.

Whether you use Save or Save As, the picture is compressed, and the compression
causes loss.

--
Rude T-shirts for a rude age: http://www.villaintees.com
Art, literature, shareware, polyamory, kink, and more:
http://www.xeromag.com/franklin.html

 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by WStoreyI » Thu, 25 Dec 2003 08:36:33


Thank you,

I did  not expect so much help and advice on the matter but you have been
very helpfull.

Happy Holidays

Quote:> >1. Where did you learn that jpg corrupts files? Nonsense.

> I suspect the original poster meant that JPEG degrades image
quality--which it
> does.

> >2. Your camera is sRGB, your video display is sRGB. All printers are
CMYK.

> The camera and video display are RGB. sRGB is a color space; it can be
assigned
> to an image for display on a device, or assigned to an image captured by a
> device, but the camera and video display are not sRGB. sRGB is a
definition of
> a working color space, not a device.

> >We used .tif in the old days because resolution was poor and "save as"
jpg
> >many times would degrade the image.

> Save As in JPEG multiple times will still cause cumulative degredation.
TIFF is
> a good, universal format for uncompressed or losslessly compressed images;
it
> is not useful only for low-resolution images.

> >Things have changed dramatically and unless you want to print very
> >large (by large I mean more than 12 x 18) from a pro shop there is
> >absolutely no advantage to save tif files over jpg.

> JPEG is lossy. TIFF is not. You may not be able to see the loss
personally, but
> I can, and others can too.

> JPEG is only useful if you are short on space, and file size is more
important
> than quality. In the day of $80 hard drives, if you are so short on space
you
> care more about file size than about quality, you need a bigger hard
drive.

> >The first point is, every time you "Save as" a jpg there is a little loss
> >and artifacts introduced, so if you edit a picture and you Save as many
> >time, there is some degradation with each Save as, but not with Save if
> >you
> >use Save to save your changes as you are editing

> Incorrect. Saving a JPEG creates cumulative degredation. If you edit the
image
> and then Save, it does the same re-compression as if you had used Save As.

> You can verify this for yourself easily.

> Whether you use Save or Save As, the picture is compressed, and the
compression
> causes loss.

> --
> Rude T-shirts for a rude age: http://www.villaintees.com
> Art, literature, shareware, polyamory, kink, and more:
> http://www.xeromag.com/franklin.html

 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by Jimm » Thu, 25 Dec 2003 13:52:32



Quote:> I have seen a lot of debat on this issue today since posting this,

> since the general concensus seems to be that since the camera captured the
> picture in jpg that it is already damaged (a little) that i can at least
> save this on cd in this format and then if i choose to edit save it as a psd
> or a tiff.

I have taken this approach.  I save the camera's jpg image file to Tiff format.  Then I make any
necessary adjustments and resave to the Tiff files.  I then archive these Tiff files on CD-R and
convert back to jpg when needed.  Continually re-saving jpg's will cause the image to degrade over
time.   Experiment for yourself by saving a image file in two formats, one in tiff and the other in
jpg.  Then make 4-5 sets of image adjustments, re-saving between each adjustment.  You will discover
for yourself which is the better method.
 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by Paul Furma » Thu, 25 Dec 2003 14:29:00


 >

Quote:> ...there is some degradation with each Save as, but not with Save if you
> use Save to save your changes as you are editing...

Hmm, I did a little test:

Open a drawing, zoom way way way in close and saveas under a different
filename... when it asks for the jpeg compression ratio, slide the bar
way over to 1 or 2 & you can see the effect of the compression as you
slide (PS 5.5). Hold it there for a moment to allow the preview to
calculate. Now, as soon as you click OK to make the save, it returns to
the good quality so what you have in the editor is still tiff quality
(unless you crash). Save or saveas doesn't matter.

I normally save minor crops & adjustments for photo shoots in jpeg
(under a different file name) and I agree it doesn't usually matter much
except very large prints as long as the quality is above 7 or 8. I keep
the original just in case. If it's special I'll save at a quality of 12
which is still smaller than a tiff & it's nice not to have all different
file types (perhaps a trivial point).

Where it does matter though is with a big simple gradually transitioning
sky, especially if you are going to do some increase in contrast with
that. Really detailed fussy pictures will not be affected as much and
won't compress as well in file size either.

Also, photoshop remembers the jpeg quality setting I used last if it was
last saved in photoshop. If direct from the digicam, it doesn't know
what setting to use and takes the last ratio I used before shutting down
photoshop (and rebooting?). But I can close an image that was saved at a
ratio of 2, shut down PS & reopen it, do a blurr & saveas remembers the
2 setting. I'm a little  unclear exactly what to expect here but those
are my results.

For important professional products, the hard drive space is cheap though.

 
 
 

Saving Pictures in Tiff CMYK or RGB??

Post by Sunn » Thu, 25 Dec 2003 16:29:27



Quote:> Just do the experiment yourself.
> You have a 3 MP camera. You have the option to save in .jpg or .tif.
> Take the same picture, one in jpg and one in tif

<snip>
All the canon cameras I have looked at(digital Compacts) only have one
format :
Still image:
 JPEG (Exif 2.2 compliant)

Are the cameras that can do "tif" only the expensive ones ?

 
 
 

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