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Increasing the file size of a digital photo

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Anonymous
May 16, 2005 1:35:51 AM

Archived from groups: rec.photo.digital (More info?)

With Adobe Photoshop, when you use the "file" "save as" command, you have
the option of creating a large file of the digital picture, with the maximum
quality being No. 12. I have found that this can increase the original size
of the digital image substantially. In one case, the original size of the
photo was 655k, and after using the "file" "save" "as" command a few times,
the file size increased almost three-fold to 1.95Mb.

I would be grateful if anyone could tell me whether printing from the 1.95Mb
file can actually provide you with a better picture than the original file
of 655k? I have my doubts and I wonder if the 1.95Mb file might actually
produce printed pictures that are more grainy than the original 655k file?
Are you in effect creating more pixels with this enlargement of the file
size process, or is it better to stick with the original smaller file?

Thanks for your help.
Anonymous
May 16, 2005 1:35:52 AM

Archived from groups: rec.photo.digital (More info?)

On Sun, 15 May 2005 21:35:51 +1200, in rec.photo.digital "Jim 34"
<jim34@dig.org> wrote:

>With Adobe Photoshop, when you use the "file" "save as" command, you have
>the option of creating a large file of the digital picture, with the maximum
>quality being No. 12. I have found that this can increase the original size
>of the digital image substantially. In one case, the original size of the
>photo was 655k, and after using the "file" "save" "as" command a few times,
>the file size increased almost three-fold to 1.95Mb.
>
>I would be grateful if anyone could tell me whether printing from the 1.95Mb
>file can actually provide you with a better picture than the original file
>of 655k? I have my doubts and I wonder if the 1.95Mb file might actually
>produce printed pictures that are more grainy than the original 655k file?
>Are you in effect creating more pixels with this enlargement of the file
>size process, or is it better to stick with the original smaller file?

No, they have the same number of pixels all you are doing is changing how
the are stored. A jpeg is stored using a lossy compression algorithm. How
lossy depends upon the quality. You start with a given image in memory and
then save it using compression. In that process you lose information. You
can't ever get that back, though you can then store this information in
ways that take up more file space. You could save as a tif and it would be
a lot bigger still as stored on the disk. You win nothing just by doing
this or printing from it. If however you intend to edit an image
repeatedly, then changing over to a non-lossy format such as tif or psd is
helpful. Every time you save to jpeg, you recompress the image and lose
information from it.
----------
Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com)
See images taken with my CP-990/5700 & D70 at
http://edwardgruf.com/Digital_Photography/General/index...
Anonymous
May 16, 2005 1:35:52 AM

Archived from groups: rec.photo.digital (More info?)

"Jim 34" <jim34@dig.org> writes:

> With Adobe Photoshop, when you use the "file" "save as" command, you
> have the option of creating a large file of the digital picture,
> with the maximum quality being No. 12. I have found that this can
> increase the original size of the digital image substantially. In
> one case, the original size of the photo was 655k, and after using
> the "file" "save" "as" command a few times, the file size increased
> almost three-fold to 1.95Mb.
>
> I would be grateful if anyone could tell me whether printing from
> the 1.95Mb file can actually provide you with a better picture than
> the original file of 655k?

No

Every time you edit a file and re-save in JPEG, artefacts accumulate.
Saving at quality level 12 will minimize this, but because artefacts
accumulate, and the quality you get will always be worse than the
original.

> I have my doubts and I wonder if the 1.95Mb file might actually
> produce printed pictures that are more grainy than the original 655k
> file? Are you in effect creating more pixels with this enlargement
> of the file size process,

No more pixels, put less JPEG compression.

> or is it better to stick with the original smaller file?

Stick to the original file, unless you /need/ to edit it.
In that case, don't save in JPEG at all, but in a non-lossy
format such as PSD, PNG or TIFF.
--
- gisle hannemyr [ gisle{at}hannemyr.no - http://folk.uio.no/gisle/ ]
------------------------------------------------------------------------
Kodak DCS460, Canon Powershot G5, Olympus 2020Z
------------------------------------------------------------------------
Related resources
Anonymous
May 16, 2005 1:35:52 AM

Archived from groups: rec.photo.digital (More info?)

Hey Jim,

In short, no.

Any modifications you've made aside, printed results can only improve
with more detail. Resaving it can't create or make up detail that
wasn't there to begin with.

Cheers,
Jules
http://www.shuttertalk.com - the friendliest digital photography forums
on the net!

Jim 34 wrote:
> With Adobe Photoshop, when you use the "file" "save as" command, you
have
> the option of creating a large file of the digital picture, with the
maximum
> quality being No. 12. I have found that this can increase the
original size
> of the digital image substantially. In one case, the original size of
the
> photo was 655k, and after using the "file" "save" "as" command a few
times,
> the file size increased almost three-fold to 1.95Mb.
>
> I would be grateful if anyone could tell me whether printing from the
1.95Mb
> file can actually provide you with a better picture than the original
file
> of 655k? I have my doubts and I wonder if the 1.95Mb file might
actually
> produce printed pictures that are more grainy than the original 655k
file?
> Are you in effect creating more pixels with this enlargement of the
file
> size process, or is it better to stick with the original smaller
file?
>
> Thanks for your help.
Anonymous
May 16, 2005 1:35:52 AM

Archived from groups: rec.photo.digital (More info?)

Jim 34 wrote:

> With Adobe Photoshop, when you use the "file" "save as" command, you have
> the option of creating a large file of the digital picture, with the maximum
> quality being No. 12. I have found that this can increase the original size
> of the digital image substantially. In one case, the original size of the
> photo was 655k, and after using the "file" "save" "as" command a few times,
> the file size increased almost three-fold to 1.95Mb.
>
> I would be grateful if anyone could tell me whether printing from the 1.95Mb
> file can actually provide you with a better picture than the original file
> of 655k?


I assume you're speaking of JPEG files.

JPEG files use a lossy compression scheme. This loss provides JPEG
with an extremely high ratio of compression. Note that regardless of
the file size, JPEG never changes the number of pixels in the file.
The compression discards *color* information in the pixles.

Light to medium compression results in very small color changes.
This works because the color differences are generally too subtle for
the eye to see. You can only compress to a certain point. With strong
compression you start introducing visible banding and splotches.

Once a file has been compressed and the color information lost, there is
no way to get it back. What you are doing is compressing the file again
using less compression. Less compression results in a larger file size,
but you can never get back what was lost when you first compressed the file.
You're gaining nothing resolution wise.. You're just losing disk space :) 

It's not a good idea to save JPEG images more than once or twice because
of the possibility of compression loss *each* time you save. If you plan
to save an image with the thoughts of doing further editing, it's
best to save in TIFF or better yet, native PSD format.


> I have my doubts and I wonder if the 1.95Mb file might actually
> produce printed pictures that are more grainy than the original 655k file?
> Are you in effect creating more pixels with this enlargement of the file
> size process, or is it better to stick with the original smaller file?
>
> Thanks for your help.
Anonymous
May 16, 2005 1:35:52 AM

Archived from groups: rec.photo.digital (More info?)

Jim 34 wrote:
> With Adobe Photoshop, when you use the "file" "save as" command, you have
> the option of creating a large file of the digital picture, with the maximum
> quality being No. 12. I have found that this can increase the original size
> of the digital image substantially. In one case, the original size of the
> photo was 655k, and after using the "file" "save" "as" command a few times,
> the file size increased almost three-fold to 1.95Mb.
>
> I would be grateful if anyone could tell me whether printing from the 1.95Mb
> file can actually provide you with a better picture than the original file
> of 655k? I have my doubts and I wonder if the 1.95Mb file might actually
> produce printed pictures that are more grainy than the original 655k file?
> Are you in effect creating more pixels with this enlargement of the file
> size process, or is it better to stick with the original smaller file?
>
> Thanks for your help.
>
>
NO.
Yes.
The file size depends on compression, so the setting may vary from the
original, but the image will NOT get better (only worse).
It is better to stick with the original, always.


--
Ron Hunter rphunter@charter.net
Anonymous
May 16, 2005 11:50:26 PM

Archived from groups: rec.photo.digital (More info?)

Thanks very much to everyone who posted a reply to this question, the
answers are most helpful. It makes me wonder why Photoshop gives you the
option to make a larger file than you had originally if it really serves no
purpose?

I see on Google Groups the following message: Note: The author of this
message requested that it not be archived. This message will be removed from
Groups in 6 days. This message appeared on the posts of Ed, Gisle, and Jim
Townsend. Because I thought the replies were excellent and probably would be
of interest to future readers, I wondered why you would not want these
valuable replies archived?

Thanks again.

Jim


"Ed Ruf" <egruf_usenet@cox.net> wrote in message
news:p dbe81tu7eu9gptrukt914o69m8385ojkn@4ax.com...
> On Sun, 15 May 2005 21:35:51 +1200, in rec.photo.digital "Jim 34"
> <jim34@dig.org> wrote:
>
>>With Adobe Photoshop, when you use the "file" "save as" command, you have
>>the option of creating a large file of the digital picture, with the
>>maximum
>>quality being No. 12. I have found that this can increase the original
>>size
>>of the digital image substantially. In one case, the original size of the
>>photo was 655k, and after using the "file" "save" "as" command a few
>>times,
>>the file size increased almost three-fold to 1.95Mb.
>>
>>I would be grateful if anyone could tell me whether printing from the
>>1.95Mb
>>file can actually provide you with a better picture than the original file
>>of 655k? I have my doubts and I wonder if the 1.95Mb file might actually
>>produce printed pictures that are more grainy than the original 655k file?
>>Are you in effect creating more pixels with this enlargement of the file
>>size process, or is it better to stick with the original smaller file?
>
> No, they have the same number of pixels all you are doing is changing how
> the are stored. A jpeg is stored using a lossy compression algorithm. How
> lossy depends upon the quality. You start with a given image in memory and
> then save it using compression. In that process you lose information. You
> can't ever get that back, though you can then store this information in
> ways that take up more file space. You could save as a tif and it would be
> a lot bigger still as stored on the disk. You win nothing just by doing
> this or printing from it. If however you intend to edit an image
> repeatedly, then changing over to a non-lossy format such as tif or psd is
> helpful. Every time you save to jpeg, you recompress the image and lose
> information from it.
> ----------
> Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com)
> See images taken with my CP-990/5700 & D70 at
> http://edwardgruf.com/Digital_Photography/General/index...
Anonymous
May 16, 2005 11:50:27 PM

Archived from groups: rec.photo.digital (More info?)

Jim 34 wrote:
> Thanks very much to everyone who posted a reply to this question, the
> answers are most helpful. It makes me wonder why Photoshop gives you the
> option to make a larger file than you had originally if it really serves no
> purpose?
>
> I see on Google Groups the following message: Note: The author of this
> message requested that it not be archived. This message will be removed from
> Groups in 6 days. This message appeared on the posts of Ed, Gisle, and Jim
> Townsend. Because I thought the replies were excellent and probably would be
> of interest to future readers, I wondered why you would not want these
> valuable replies archived?
>
> Thanks again.
>
> Jim


Jim,
The option is provided because the less compression done, the less
data is degraded for each save. This means that if you save the file at
'12' quality, 6 times between edits, and do the same at '8' quality 6
times between edits, less degradation of the file will (theoretically)
take place for the '12' quality saves.
So, if you just MUST keep the .jpg format, and you must do repeated
edits, select the larger file size and lose less data each save.

>
>
>


--
Ron Hunter rphunter@charter.net
Anonymous
May 17, 2005 12:37:52 AM

Archived from groups: rec.photo.digital (More info?)

"Gisle Hannemyr" <gisle+news@ifi.uio.no> wrote in message
news:q5zmuwvisk.fsf@kolme.ifi.uio.no...
> "Jim 34" <jim34@dig.org> writes:
>
>> With Adobe Photoshop, when you use the "file" "save as" command, you
>> have the option of creating a large file of the digital picture,
>> with the maximum quality being No. 12. I have found that this can
>> increase the original size of the digital image substantially. In
>> one case, the original size of the photo was 655k, and after using
>> the "file" "save" "as" command a few times, the file size increased
>> almost three-fold to 1.95Mb.
>>
>> I would be grateful if anyone could tell me whether printing from
>> the 1.95Mb file can actually provide you with a better picture than
>> the original file of 655k?
>
> No
>
> Every time you edit a file and re-save in JPEG, artefacts accumulate.
> Saving at quality level 12 will minimize this, but because artefacts
> accumulate, and the quality you get will always be worse than the
> original.
>
>> I have my doubts and I wonder if the 1.95Mb file might actually
>> produce printed pictures that are more grainy than the original 655k
>> file? Are you in effect creating more pixels with this enlargement
>> of the file size process,
>
> No more pixels, put less JPEG compression.
>
>> or is it better to stick with the original smaller file?
>
> Stick to the original file, unless you /need/ to edit it.
> In that case, don't save in JPEG at all, but in a non-lossy
> format such as PSD, PNG or TIFF.

Thanks for this reply Gisle. Because the picture was originally taken as a
JPEG, is there any advantage in later saving it as a PSD, PNG or TIFF,
because as has been explained to me here, you can't improve on the original?
Will the artifacts accumulate less as you keep editing and saving the photo
if, before you start editing it, you first convert the file from a JPEG to a
TIFF, for example?

Regards, Jim
Anonymous
May 17, 2005 12:37:53 AM

Archived from groups: rec.photo.digital (More info?)

"Jim 34" <jim34@dig.org> writes:
> Thanks for this reply Gisle. Because the picture was originally taken as a
> JPEG, is there any advantage in later saving it as a PSD, PNG or TIFF,
> because as has been explained to me here, you can't improve on the original?
> Will the artifacts accumulate less as you keep editing and saving the photo
> if, before you start editing it, you first convert the file from a JPEG to a
> TIFF, for example?

Yes, that's the right way to do multiple edits. Convert to TIFF when
you first start working on the image, do all your edits in TIFF, and
covert back to JPEG at the end.
Anonymous
May 17, 2005 12:37:53 AM

Archived from groups: rec.photo.digital (More info?)

"Jim 34" <jim34@dig.org> writes:
> "Gisle Hannemyr" <gisle+news@ifi.uio.no> wrote:
>> "Jim 34" <jim34@dig.org> writes:

>>> With Adobe Photoshop, when you use the "file" "save as" command,
>>> you have the option of creating a large file of the digital
>>> picture, with the maximum quality being No. 12. I have found that
>>> this can increase the original size of the digital image
>>> substantially. In one case, the original size of the photo was
>>> 655k, and after using the "file" "save" "as" command a few times,
>>> the file size increased almost three-fold to 1.95Mb.
>>>
>>> I would be grateful if anyone could tell me whether printing from
>>> the 1.95Mb file can actually provide you with a better picture
>>> than the original file of 655k?

>> No
>>
>> Every time you edit a file and re-save in JPEG, artefacts
>> accumulate. Saving at quality level 12 will minimize this, but
>> because artefacts accumulate, the quality you get will always be
>> worse than the original.
>>
>> Stick to the original file, unless you /need/ to edit it.
>> In that case, don't save in JPEG at all, but in a non-lossy
>> format such as PSD, PNG or TIFF.

> Thanks for this reply Gisle. Because the picture was originally
> taken as a JPEG, is there any advantage in later saving it as a PSD,
> PNG or TIFF, because as has been explained to me here, you can't
> improve on the original?

Well, you can /edit/ the original in Photoshop (to correct colour
casts, improve contrasts, clone away unwanted details, sharpen, etc.).
The idea is that /if/ you edit, you don't save the intermediate edited
versions in JPEG, but save them in a non-lossy format such as PSD, PNG
or TIFF. There is a lot more to this than meets the eye. I would
suggest you Google for: ┬źdigital workflow -rockwell┬╗.

> Will the artifacts accumulate less as you keep editing and saving
> the photo if, before you start editing it, you first convert the
> file from a JPEG to a TIFF, for example?

They will not accumulate at all! You will of course still have those
you started out with if the camera originally saved the photograph as
a JPEG, but if you use your camera's "best" JPEG quality, the
original artefacts will be very difficult to spot for an untrained
eye. By using a non-lossy format for subsequent edits, you ensure
that that no /new/ JPEG-compression artefacts will be introduced
into the image.

For sharing photographs on the web, and for printing at consumer labs
such as Walmart and Costco, JPEG is the appropriate format. So after
you've finished editing - you would normally save the final version
as a JPEG again.

Finally: If you don't want any JPEG-compression artefacts in your
photograph to begin with, you make the camera save them in a non-lossy
format such as RAW (or TIFF). Only the more expensive cameras
provides this as an option, tho'.
--
- gisle hannemyr [ gisle{at}hannemyr.no - http://folk.uio.no/gisle/ ]
------------------------------------------------------------------------
Kodak DCS460, Canon Powershot G5, Olympus 2020Z
------------------------------------------------------------------------
Anonymous
May 17, 2005 12:37:53 AM

Archived from groups: rec.photo.digital (More info?)

Jim 34 wrote:
> "Gisle Hannemyr" <gisle+news@ifi.uio.no> wrote in message
> news:q5zmuwvisk.fsf@kolme.ifi.uio.no...
>
>>"Jim 34" <jim34@dig.org> writes:
>>
>>
>>>With Adobe Photoshop, when you use the "file" "save as" command, you
>>>have the option of creating a large file of the digital picture,
>>>with the maximum quality being No. 12. I have found that this can
>>>increase the original size of the digital image substantially. In
>>>one case, the original size of the photo was 655k, and after using
>>>the "file" "save" "as" command a few times, the file size increased
>>>almost three-fold to 1.95Mb.
>>>
>>>I would be grateful if anyone could tell me whether printing from
>>>the 1.95Mb file can actually provide you with a better picture than
>>>the original file of 655k?
>>
>>No
>>
>>Every time you edit a file and re-save in JPEG, artefacts accumulate.
>>Saving at quality level 12 will minimize this, but because artefacts
>>accumulate, and the quality you get will always be worse than the
>>original.
>>
>>
>>>I have my doubts and I wonder if the 1.95Mb file might actually
>>>produce printed pictures that are more grainy than the original 655k
>>>file? Are you in effect creating more pixels with this enlargement
>>>of the file size process,
>>
>>No more pixels, put less JPEG compression.
>>
>>
>>>or is it better to stick with the original smaller file?
>>
>>Stick to the original file, unless you /need/ to edit it.
>>In that case, don't save in JPEG at all, but in a non-lossy
>>format such as PSD, PNG or TIFF.
>
>
> Thanks for this reply Gisle. Because the picture was originally taken as a
> JPEG, is there any advantage in later saving it as a PSD, PNG or TIFF,
> because as has been explained to me here, you can't improve on the original?
> Will the artifacts accumulate less as you keep editing and saving the photo
> if, before you start editing it, you first convert the file from a JPEG to a
> TIFF, for example?
>
> Regards, Jim
>
>
Yes! That is, if you continue saving each iteration of the file as a
TIFF file until all editing is done, no further compression degradation
will occur.


--
Ron Hunter rphunter@charter.net
Anonymous
May 17, 2005 12:37:54 AM

Archived from groups: rec.photo.digital (More info?)

Paul Rubin <http://phr.cx@nospam.invalid&gt; wrote:
: "Jim 34" <jim34@dig.org> writes:
: > Thanks for this reply Gisle. Because the picture was originally taken
: > as a JPEG, is there any advantage in later saving it as a PSD, PNG or
: > TIFF, because as has been explained to me here, you can't improve on
: > the original? Will the artifacts accumulate less as you keep editing
: > and saving the photo if, before you start editing it, you first
: > convert the file from a JPEG to a TIFF, for example?

: Yes, that's the right way to do multiple edits. Convert to TIFF when
: you first start working on the image, do all your edits in TIFF, and
: covert back to JPEG at the end.

Correct. The fewer conversions that require some degree of loss the
better. But you do not have to go all the way to TIFF. Since you mentioned
PS, you can use the default photoshop format for all intermediate saves.
This format is a "no loss" format. So when you load the original JPG file
there will be no loss (as the conversion is from any format to a lossless
one). If you keep all saves along the way in the lossless domain no
further data will be lost (at least due to conversion errors). Then the
final conversion to JPG for long term storage will be the only
conversion. If the "quality" of the conversion is high enough the loss
will be minimal. It is only with low quality conversions or repeated (>5
to 10) reconversions that the conversion errors build up to a noticeable
level (to all but the most picky of us or if the print size is too large,
such as >8x10). The more conversions the smaller the print needs to be to
cover any conversion errors. So if you are working on posters, you may
want to think about removing JPG from the string all together. But if you
are working on a final product that will only be used as a 4x5 print you
could even get by with 15 to 20 (or possibly more) reconversions with
little noticeable inacuracies. Of course this is not a hard and fast rule
as some images are much more prone to noticeable rendition errors. :)  This
is why many of us recommend saving the original image just as it comes out
of the camera immediately. This way if too many conversions, or other
processes, make the edited image unusable, you can go back to the
beginning and start over fresh. :) 

Randy

==========
Randy Berbaum
Champaign, IL
Anonymous
May 17, 2005 12:37:54 AM

Archived from groups: rec.photo.digital (More info?)

Paul Rubin wrote:
> "Jim 34" <jim34@dig.org> writes:
>
>>Thanks for this reply Gisle. Because the picture was originally taken as a
>>JPEG, is there any advantage in later saving it as a PSD, PNG or TIFF,
>>because as has been explained to me here, you can't improve on the original?
>>Will the artifacts accumulate less as you keep editing and saving the photo
>>if, before you start editing it, you first convert the file from a JPEG to a
>>TIFF, for example?
>
>
> Yes, that's the right way to do multiple edits. Convert to TIFF when
> you first start working on the image, do all your edits in TIFF, and
> covert back to JPEG at the end.
If using Photoshop, or Photoshop Elements, there is a definite advantage
to using the PSD format for interim saves as it tracks the process of
editing, and maintains things like layers between saves so that editing
can be resumed where you left off.


--
Ron Hunter rphunter@charter.net
Anonymous
May 17, 2005 12:37:55 AM

Archived from groups: rec.photo.digital (More info?)

Randy Berbaum wrote:
>
> PS, you can use the default photoshop format for all intermediate saves.


Note that you can save as jpeg as many times as you like during a single
editing session and there is no cumulative damage until you close the file.

--
Paul Furman
http://www.edgehill.net/1
san francisco native plants
Anonymous
May 17, 2005 12:37:56 AM

Archived from groups: rec.photo.digital (More info?)

Paul Furman wrote:
> Randy Berbaum wrote:
>
>>
>> PS, you can use the default photoshop format for all intermediate saves.
>
>
>
> Note that you can save as jpeg as many times as you like during a single
> editing session and there is no cumulative damage until you close the file.
>
ANY time you save a file to .jpg, it is recompressed if it has changed
significantly. Each recompression accumulates errors. If you mean that
you can load the file, then do edits, saving each step, and then do a
final save of the last edit, deleting the interim saves, yes, I agree.
But reloading one of the interim saves then continuing from there would
cost some data.


--
Ron Hunter rphunter@charter.net
!