|  | Image Quality | | |
| | | Mike Wright |  |
|  Posted: Mon Jul 07, 2008 2:52 pm Post subject: Image Quality |  |
For some years I have been using PSP9 in conjunction with Paint Shop Photo
Album v5.0.1
I import photos from my digital camera into Photo Album and then process
them with Paintshop and then save in Photo Album. I have noticed many times
that the file size reduces considerably during this process. I can step
through this process and take an image into Paintshop and save back to Photo
Album without carrying out any processing whatsoever and the file size is
still considerably reduced even though the pixel size of the image remains
the same. My question is - 'Has the image lost any quality as the result of
this process'? If the quality remains unchanged - please explain in simple
terms how this is achieved |
| |
| | | Trev | |
| | Posted: Mon Jul 07, 2008 3:18 pm Post subject: Re: Image Quality | |
| |  | |
In news:48724865$1_2@cnews,
<mawright10@tiscali.co.uk> Mike Wright bashed on keyboard and typed:
| Quote: | For some years I have been using PSP9 in conjunction with Paint Shop
Photo Album v5.0.1
I import photos from my digital camera into Photo Album and then
process them with Paintshop and then save in Photo Album. I have
noticed many times that the file size reduces considerably during
this process. I can step through this process and take an image into
Paintshop and save back to Photo Album without carrying out any
processing whatsoever and the file size is still considerably reduced
even though the pixel size of the image remains the same. My question
is - 'Has the image lost any quality as the result of this process'?
If the quality remains unchanged - please explain in simple terms how
this is achieved
|
One assumes that you are using jpeg. This is a lossey compression format
where depending on the compression chosen, it will look for pixels of a
similarity to the next to it. how similarity depends of the compression
factor. having found the it saves one and maps the location of the others
then deletes them. so the saved image becomes smaller in file size. When it
is opened the image is rebuilt by creating copies of the saved pixel and
painting them into the location of the missing ones.
If you had not made any changes to the image then you would not have had to
save it just closed it.
If you keep resaving you will eventually finish with a bad image as each
time you lose a bit more detail.
Its best to use a lossless format such as PSP image or Tiff both of which
can use LZW lossless compression which will save a little hard disc space.
PNG would also be a good chose.
--
Trev
Nobody is perfect.
But Being a Yorkshire man is as close as you can get. |
| |
| | | cosake | |
| | Posted: Mon Jul 07, 2008 3:21 pm Post subject: Re: Image Quality | |
| | | |
Hi Mike -
You don't say what file format or compression level you are using, etc. I
think more information is needed about your exact process before this can be
answered sufficiently.
cosake
"Mike Wright" <mawright10@tiscali.co.uk> wrote in message
news:48724865$1_2@cnews...
| Quote: |
For some years I have been using PSP9 in conjunction with Paint Shop
Photo Album v5.0.1
I import photos from my digital camera into Photo Album and then process
them with Paintshop and then save in Photo Album. I have noticed many
times that the file size reduces considerably during this process. I can
step through this process and take an image into Paintshop and save back
to Photo Album without carrying out any processing whatsoever and the file
size is still considerably reduced even though the pixel size of the image
remains the same. My question is - 'Has the image lost any quality as the
result of this process'? If the quality remains unchanged - please explain
in simple terms how this is achieved
|
|
| |
| | | Jewels | |
| | Posted: Mon Jul 07, 2008 3:29 pm Post subject: Re: Image Quality | |
| | | |
Mike Wright wrote:
| Quote: | For some years I have been using PSP9 in conjunction with Paint Shop
Photo Album v5.0.1
I import photos from my digital camera into Photo Album and then
process them with Paintshop and then save in Photo Album. I have
noticed many times that the file size reduces considerably during
this process. I can step through this process and take an image into
Paintshop and save back to Photo Album without carrying out any
processing whatsoever and the file size is still considerably reduced
even though the pixel size of the image remains the same. My question
is - 'Has the image lost any quality as the result of this process'?
If the quality remains unchanged - please explain in simple terms how
this is achieved
|
Hi Mike,
it depends on what format you save the file in. Some formats compress a
picture losslessly, eg PSP. However, if it's saved as a JPG, you lose some
information every time to save the file and this is the most likely format
that your photos are in from the camera. I don't use Photo Album so I'm not
sure what formats are available to you there.
The basic advice is to save your pictures as a PSP image file because it
will maintain all the quality and features (eg layers) that are in the file
at the point you save it. You can go back and do further edits and save
again in this way with no loss of quality. When you have finished editing
and want to share it with people who don't have PSP, export a copy using the
JPG optimiser which gives you a preview of what your file will look like
after saving.
You can probably find more detailed information by searching old posts in
this and other PSP groups or by Googling JPG compression on the web.
Julie |
| |
| | | Mike Wright | |
| | Posted: Mon Jul 07, 2008 9:57 pm Post subject: Re: Image Quality | |
| | | |
Hi Trev
Thanks for the quick response. Yes I am importing jpeg via TWAIN from my
camera into Paintshop Photo Album. This gives me acceptable quality for my
general photo storage requirements. I then export each jpeg image as
necessary directly to PSP9 for general 'titivating'. i.e. cropping,
brightness/contrast adjustments, cloning out unwanted objects & other
related tasks as necessary. I then hit the 'save' key to store each modified
image in place of the original. It is at this stage that the file size is
considerably reduced. I would prefer that the 'save' command stored the
modified image at the same compression as the original but have not found
the way to do this. ( I feel sure that PSP9 has a way of doing this and this
is where I would welcome some help). I know that I can use 'save as';
'export'; & jpeg optimiser commands to change compression ratio, etc., but
this involves creating copies, deleting originals, etc., & lengthens the
process considerably, particularly as I often have many images to process. I
am also aware that I can work in other lossless formats but for my general
purposes I do not need to do this.
Regards - Mike
"Trev" <trevbowden@dsl.pipex.cominvalid> wrote in message
news:48724f65_2@cnews...
| Quote: |
In news:48724865$1_2@cnews,
mawright10@tiscali.co.uk> Mike Wright bashed on keyboard and typed:
For some years I have been using PSP9 in conjunction with Paint Shop
Photo Album v5.0.1
I import photos from my digital camera into Photo Album and then
process them with Paintshop and then save in Photo Album. I have
noticed many times that the file size reduces considerably during
this process. I can step through this process and take an image into
Paintshop and save back to Photo Album without carrying out any
processing whatsoever and the file size is still considerably reduced
even though the pixel size of the image remains the same. My question
is - 'Has the image lost any quality as the result of this process'?
If the quality remains unchanged - please explain in simple terms how
this is achieved
One assumes that you are using jpeg. This is a lossey compression format
where depending on the compression chosen, it will look for pixels of a
similarity to the next to it. how similarity depends of the compression
factor. having found the it saves one and maps the location of the others
then deletes them. so the saved image becomes smaller in file size. When
it is opened the image is rebuilt by creating copies of the saved pixel
and painting them into the location of the missing ones.
If you had not made any changes to the image then you would not have had
to save it just closed it.
If you keep resaving you will eventually finish with a bad image as each
time you lose a bit more detail.
Its best to use a lossless format such as PSP image or Tiff both of which
can use LZW lossless compression which will save a little hard disc space.
PNG would also be a good chose.
--
Trev
Nobody is perfect.
But Being a Yorkshire man is as close as you can get.
|
|
| |
| | | Mike Wright | |
| | Posted: Mon Jul 07, 2008 10:29 pm Post subject: Re: Image Quality | |
| | | |
Hi cosake,
Thanks for your reply. Please refer to my response to 'Trev' for more
information.
Regards - Mike
"cosake" <cosake@NOSPAMtangoware.com> wrote in message
news:4872501a$1_1@cnews...
| Quote: |
Hi Mike -
You don't say what file format or compression level you are using, etc. I
think more information is needed about your exact process before this can
be answered sufficiently.
cosake
"Mike Wright" <mawright10@tiscali.co.uk> wrote in message
news:48724865$1_2@cnews...
For some years I have been using PSP9 in conjunction with Paint Shop
Photo Album v5.0.1
I import photos from my digital camera into Photo Album and then process
them with Paintshop and then save in Photo Album. I have noticed many
times that the file size reduces considerably during this process. I can
step through this process and take an image into Paintshop and save back
to Photo Album without carrying out any processing whatsoever and the
file size is still considerably reduced even though the pixel size of the
image remains the same. My question is - 'Has the image lost any quality
as the result of this process'? If the quality remains unchanged - please
explain in simple terms how this is achieved
|
|
| |
| | | Mike Wright | |
| | Posted: Mon Jul 07, 2008 10:32 pm Post subject: Re: Image Quality | |
| | | |
Hi Jewels,
Thanks for your help. Please see my reply to Trev for further details.
Regards - Mike
"Jewels" <stuart_julie@hotmail.com> wrote in message
news:48725100$1_3@cnews...
| Quote: |
Mike Wright wrote:
For some years I have been using PSP9 in conjunction with Paint Shop
Photo Album v5.0.1
I import photos from my digital camera into Photo Album and then
process them with Paintshop and then save in Photo Album. I have
noticed many times that the file size reduces considerably during
this process. I can step through this process and take an image into
Paintshop and save back to Photo Album without carrying out any
processing whatsoever and the file size is still considerably reduced
even though the pixel size of the image remains the same. My question
is - 'Has the image lost any quality as the result of this process'?
If the quality remains unchanged - please explain in simple terms how
this is achieved
Hi Mike,
it depends on what format you save the file in. Some formats compress a
picture losslessly, eg PSP. However, if it's saved as a JPG, you lose
some
information every time to save the file and this is the most likely format
that your photos are in from the camera. I don't use Photo Album so I'm
not
sure what formats are available to you there.
The basic advice is to save your pictures as a PSP image file because it
will maintain all the quality and features (eg layers) that are in the
file
at the point you save it. You can go back and do further edits and save
again in this way with no loss of quality. When you have finished editing
and want to share it with people who don't have PSP, export a copy using
the
JPG optimiser which gives you a preview of what your file will look like
after saving.
You can probably find more detailed information by searching old posts in
this and other PSP groups or by Googling JPG compression on the web.
Julie
|
|
| |
| | | JoeB | |
| | Posted: Tue Jul 08, 2008 2:41 am Post subject: Re: Image Quality | |
| | | |
"Mike Wright" <mawright10@tiscali.co.uk> wrote in news:4872ac08_2@cnews:
| Quote: |
Hi Trev
Thanks for the quick response. Yes I am importing jpeg via TWAIN from
my camera into Paintshop Photo Album. This gives me acceptable quality
for my general photo storage requirements. I then export each jpeg
image as necessary directly to PSP9 for general 'titivating'. i.e.
cropping, brightness/contrast adjustments, cloning out unwanted
objects & other related tasks as necessary. I then hit the 'save' key
to store each modified image in place of the original. It is at this
stage that the file size is considerably reduced.
|
If you are cropping an image then you should expect its file size to be
reduced. There's less image data to save so why would you expect a the
file size not to be reduced? It's like taking a loaft of bread that
weighs 16 ounces and cropping off the ends. You wouldn't expect the
stuff saved in the middle to still weigh 16 ounces, would you?
| Quote: | I would prefer that
the 'save' command stored the modified image at the same compression
as the original but have not found the way to do this.
|
You don't know what the compression level setting was in the original.
PSP doesn't know that either, and neither do any other graphic programs.
Not only that, virtually all graphic programs and cameras use
differently configured algorithms to do jpg compression, so even if your
graphic program knew the compression that your camera used when saving
jpgs your graphic and it set itself for that compression number the
results would still be different.
Besides the above, you obviously need more knowledge about compression
as a subject. Even if you open the image in PSP and don't crop but just
add sharpening, and even if PSP used exactly the same compression level
and algorithm as the camera from which the image came, the final saved
output size would be different from the size of the input image because
the sharpening would cause the size to be larger - because it's harder
to compress a sharpened image than a non-sharpened one.
And if you're using Save instead of the jpg optimizer, then it will save
at whatever the last default compression setting was when you saved an
image that way. And all of your cropping and whatever else you do is
going to affect the final size of the image.
| Quote: | ( I feel sure
that PSP9 has a way of doing this and this is where I would welcome
some help).
|
I'm afraid you are in error, regardless of what you might feel PSP might
be able to do. It can't, and neither can any other program.
| Quote: | I know that I can use 'save as'; 'export'; & jpeg
optimiser commands to change compression ratio, etc., but this
involves creating copies, deleting originals, etc. & lengthens the
process considerably, particularly as I often have many images to
process.
|
It doesn't involve any such thing. You can export using the jpg
optimizer and then save it with the same file name in the same folder as
the original and it will simply overwrite the original file you opened.
When you use Save it does the same thing, except you have no control
over the compression level and therefore final file size on disc - which
seems to be the thing that you are so concerned with at the moment.
And I repeat, the only way you can have some control over that is to use
the jpg optimizer.
| Quote: | I am also aware that I can work in other lossless formats but
for my general purposes I do not need to do this.
|
Then do what you have been advised and use the jpg optimizer if it is
necessary for you to try to get the final output file size on disc
approximately the same as the input file size was.
In real life, matching output file size to input files size, assuming
that the final output has been cropped and otherwise maniupulated, is a
useless excercise and provides no benefit whatsoever. But then so is
searching for the pot of gold at the end of the rainbow, and some people
seem to think it's worth it.
Regards,
JoeB
| Quote: |
Regards - Mike
"Trev" <trevbowden@dsl.pipex.cominvalid> wrote in message
news:48724f65_2@cnews...
In news:48724865$1_2@cnews,
mawright10@tiscali.co.uk> Mike Wright bashed on keyboard and typed:
For some years I have been using PSP9 in conjunction with Paint
Shop Photo Album v5.0.1
I import photos from my digital camera into Photo Album and then
process them with Paintshop and then save in Photo Album. I have
noticed many times that the file size reduces considerably during
this process. I can step through this process and take an image into
Paintshop and save back to Photo Album without carrying out any
processing whatsoever and the file size is still considerably
reduced even though the pixel size of the image remains the same. My
question is - 'Has the image lost any quality as the result of this
process'? If the quality remains unchanged - please explain in
simple terms how this is achieved
One assumes that you are using jpeg. This is a lossey compression
format where depending on the compression chosen, it will look for
pixels of a similarity to the next to it. how similarity depends of
the compression factor. having found the it saves one and maps the
location of the others then deletes them. so the saved image becomes
smaller in file size. When it is opened the image is rebuilt by
creating copies of the saved pixel and painting them into the
location of the missing ones.
If you had not made any changes to the image then you would not have
had to save it just closed it.
If you keep resaving you will eventually finish with a bad image as
each time you lose a bit more detail.
Its best to use a lossless format such as PSP image or Tiff both of
which can use LZW lossless compression which will save a little hard
disc space. PNG would also be a good chose.
--
Trev
Nobody is perfect.
But Being a Yorkshire man is as close as you can get.
|
|
| |
| | | Spandex Rutabaga | |
| | Posted: Wed Jul 09, 2008 8:26 pm Post subject: Re: Image Quality | |
| | | |
Mike Wright wrote:
| Quote: |
For some years I have been using PSP9 in conjunction with Paint Shop Photo
Album v5.0.1
I import photos from my digital camera into Photo Album and then process
them with Paintshop and then save in Photo Album. I have noticed many times
that the file size reduces considerably during this process. I can step
through this process and take an image into Paintshop and save back to Photo
Album without carrying out any processing whatsoever and the file size is
still considerably reduced even though the pixel size of the image remains
the same.
|
Probably (though you've kept this to yourself) you are saving
as JPEG and you are using a different (larger) compression
level than was used on the original image. The higher the
compression level the more image information you permanently
discard in the process of saving the file. The image in the
saved file is no longer identical to the image before the save.
| Quote: | My question is - 'Has the image lost any quality as the result of
this process'?
|
Yes.
| Quote: | If the quality remains unchanged - please explain in simple
terms how this is achieved
|
Only by a miracle :)
Make your life easier by not using lossy compression such as
that in formats like JPEG or JPEG 2000. Instead, use lossless
compression such as that in the TIFF or PNG format. Your files
will be bigger (because you are not throwing anything away)
but your image will never degrade simply because of being
saved to a file. If you must use the JPEG format save using
the PSP JPEG Optimizer so you can see the settings you are
using and preview their effect on the image. |
| |
|
|
