#1 file type question and #2 file size question

[mamedanuki]

Hello!
   
  When I tried to save some photo files
  from SAVE AS menue
  " ???????????? " (many question marks) appeared to the file type box and those files were not able to be opened with powerpoint or paintnet, only opened with IMAGE J.
  Original file was made with Macintosh photoshop. I used  windows XP after that.
  Does anyone have any idea what is wrong ?
   
  Recently I asked about resize function of IMAGE J.
  I found I can only change pixel number.
  What I want to do it to resize big file size photo like 1-2MB to 500kb photo file.
  Is that possible ?
  I know I can do that with photoshop, but currently I do not have PC version of photoshop.
   
  I would appreciate any help.
  Thanks.
   
  Chikage Sugimoto
   
   

 
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[Jonathan Hilmer]

For your second question, if you want to generate reduced-resolution
or lossy compressed versions of images you might try software such as
Gimp.  It is useful to have installed for many purposes, this being
one of them.  Imagemagick would be a good solution if you wanted to
perform this operation on huge sets of files, and of course ImageJ
would also be able to create compressed files for this kind of
operation.

Jonathan


On 8/11/06, SUGIMOTO, C <[hidden email]> wrote:

> Hello!
>
>   When I tried to save some photo files
>   from SAVE AS menue
>   " ???????????? " (many question marks) appeared to the file type box and those files were not able to be opened with powerpoint or paintnet, only opened with IMAGE J.
>   Original file was made with Macintosh photoshop. I used  windows XP after that.
>   Does anyone have any idea what is wrong ?
>
>   Recently I asked about resize function of IMAGE J.
>   I found I can only change pixel number.
>   What I want to do it to resize big file size photo like 1-2MB to 500kb photo file.
>   Is that possible ?
>   I know I can do that with photoshop, but currently I do not have PC version of photoshop.
>
>   I would appreciate any help.
>   Thanks.
>
>   Chikage Sugimoto

[Harry Parker]

You didn't say what format you selected for saving images. The TIFF format is the ImageJ default. Unfortunately, not many programs support TIFF. It is a good format for saving images losslessly, so that no detail is lost, but the files a very big.

If you are saving photos for illustrations (and not for measurements), JPEG is a good format choice. JPEG is universally supported, has good compression, but modifies the details of the image.

 JPEG may or may not be a good format for saving images for measurement, depending on what you are measuring in an image. Each time you save an image in the JPEG format, more detail is lost.

This may also be the answer to your 2nd question. JPEG memory size and quality is adjustable. You can modify the output size of a JPEG file (number of KB) trading off size for quality. Try adjusting the JPEG Quality setting before saving a file as JPEG. (Menu: Edit->Options->Input/Output...) Note the resulting file sizes as you change the quality setting. The image size will vary with the image, depending on the amount of detail and sharpness of the image. Smooth, blurry images compress better.

I am interested in preserving fine details in most of my images and so keep the JPEG quality at 95. Depending on your needs a lower setting may work well for you and save much memory. Just be sure to reopen the file after saving it and inspect it carefully to see if the details you are interested in are preserved. If not, try a higher quality setting.
 
--  
Harry Parker  
Senior Systems Engineer  
Dialog Imaging Systems, Inc.

----- Original Message ----
From: "SUGIMOTO, C" <[hidden email]>
To: [hidden email]
Sent: Friday, August 11, 2006 1:14:21 PM
Subject: #1 file type question and #2  file size question

Hello!
   
  When I tried to save some photo files
  from SAVE AS menue
  " ???????????? " (many question marks) appeared to the file type box and those files were not able to be opened with powerpoint or paintnet, only opened with IMAGE J.
  Original file was made with Macintosh photoshop. I used  windows XP after that.
  Does anyone have any idea what is wrong ?
   
  Recently I asked about resize function of IMAGE J.
  I found I can only change pixel number.
  What I want to do it to resize big file size photo like 1-2MB to 500kb photo file.
  Is that possible ?
  I know I can do that with photoshop, but currently I do not have PC version of photoshop.
   
  I would appreciate any help.
  Thanks.
   
  Chikage Sugimoto
   
   

         
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[Dimiter Prodanov]

Hi,

I definitely prefer TIFF format, because it is the publication standard for all
life science journals. Nowadays storage is not a problem; virtually
every desctop is equipped with a DVD writer or a CD writer so
making hardcopies of images is not a problem.
If really the size is your concern but you want preservation of details
for measuremet purposes I would suggest the GIF format; however
it is limited to 256 gray/color levels.

best regards


_______________________________________________________________________
Dr Dimiter Prodanov, MD, Ph.D.

Neural Engineering Rehabilitation Laboratory
(Laboratoire de Génie de la Réhabilitation Neurale)
Département de Physiologie et Pharmacologie
Université catholique de Louvain
Avenue Hippocrate, 54
POBox UCL-5446 / B-1200 Bruxelles -Belgique-
Phone: [phone]
Fax: [phone]

http://www.md.ucl.ac.be/gren

[dscho]

Hi,

On Fri, 18 Aug 2006, Dimiter Prodanov wrote:

> I definitely prefer TIFF format, because it is the publication standard
> for all life science journals. Nowadays storage is not a problem;
> virtually every desctop is equipped with a DVD writer or a CD writer so
> making hardcopies of images is not a problem.

The problem is more something of I/O. CPUs have become so powerful that it
is actually faster to load a small, compressed file _and_ decompress it,
than to load the uncompressed file.

> If really the size is your concern but you want preservation of details
> for measuremet purposes I would suggest the GIF format; however it is
> limited to 256 gray/color levels.

People _still_ use GIF? *shudders*

PNG was invented to overcome technical (256 colors) and non-technical
(Unisys bastards) issues, so you really should use PNG, which has a very
nice lossless mode.

Hth,
Dscho