Computer Graphics with Photoshop - TIF image is missing subjects!

Author

TIF image is missing subjects!

SparkyGuy

2007-06-11, 6:15 pm

Took an outdoor portrait of friends. Camera gives high-res JPG file.

P'shopped it a bit which included selecting the subjects and applying a bit
of brightness/contrast shifting. Looks good.

Saved it as a TIFF file.

Opened it up in a viewer (Preview, a Mac app) and the area that I selected
and altered the brightness/contrast of is "cut out". Gone.

All looks normal in P'shop. If it was a native P'shop file, I'm aware of
merging layers, but it's not necessary or possible in a TIFF, is it? (This
menu option is grayed-out.)

Obviously I'm missing something. Any suggestions would be greatly
appreciated.

OS X 10.3.9
Photoshop CS 8.0 (Mac)

Thanks,

John McWilliams

2007-06-11, 6:15 pm

SparkyGuy wrote:
> Took an outdoor portrait of friends. Camera gives high-res JPG file.
>
> P'shopped it a bit which included selecting the subjects and applying a bit
> of brightness/contrast shifting. Looks good.
>
> Saved it as a TIFF file.
>
> Opened it up in a viewer (Preview, a Mac app) and the area that I selected
> and altered the brightness/contrast of is "cut out". Gone.
>
> All looks normal in P'shop. If it was a native P'shop file, I'm aware of
> merging layers, but it's not necessary or possible in a TIFF, is it? (This
> menu option is grayed-out.)
>
> Obviously I'm missing something. Any suggestions would be greatly
> appreciated.
>
> OS X 10.3.9
> Photoshop CS 8.0 (Mac)

Tiffs can manage layers, but I don't think Preview likes them. Try
again, but flatten image, and save to both jpeg and tiff.

--
john mcwilliams

SparkyGuy

2007-06-11, 6:15 pm

> Tiffs can manage layers, but I don't think Preview likes them. Try
> again, but flatten image, and save to both jpeg and tiff.

"Flatten" is also grayed-out.

As a practice, I avoid saving to JPG (compression losses), but I saved this
as JPG and it appears normal.

So this is just a bug in Preview?

How come TIFF format of this file is 10x the size of JPG?

Thanks,

KatWoman

2007-06-11, 10:15 pm

"SparkyGuy" <SparkyGuy@mumcrank.ck> wrote in message
news:0001HW.C292FB160064BBCDF01826C8@news.sf.sbcglobal.net...
>
> "Flatten" is also grayed-out.
>
> As a practice, I avoid saving to JPG (compression losses), but I saved
> this
> as JPG and it appears normal.
>
> So this is just a bug in Preview?
>
> How come TIFF format of this file is 10x the size of JPG?
>
> Thanks,

you did not select compression so it is not compressed and therefore larger
than a jpg (by default compressed)
when you save the tiff look at the options
layered or flat
save or save a copy

there should be another dialog box after save re-asking the tiff save
options
some viewers cannot see the layers and only show you the top most (often
alpha) layer

tacit

2007-06-11, 10:15 pm

In article <0001HW.C292FB160064BBCDF01826C8@news.sf.sbcglobal.net>,
SparkyGuy <SparkyGuy@mumcrank.ck> wrote:

> How come TIFF format of this file is 10x the size of JPG?

Because all JPEG files are compressed.

The JPEG standard was invented for situations where file size on disk is
absolutely critical but image quality is not important. It makes the
size of the file very small on disk. It does this by intentionally
degrading the quality of the image; the image quality is sacrificed for
the purpose of a smaller file.

When you saved your TIFF, did you by any chance include any alpha
channels in the TIFF?

--
Photography, kink, polyamory, shareware, and more: all at
http://www.xeromag.com/franklin.html

SparkyGuy

2007-06-12, 6:14 pm

> Because all JPEG files are compressed.

This I know. But where is the additional pic data coming from? The original
photo is JPG, size ~1.4 MB. When I open that in Photoshop and then save as
TIF, all of a sudden it's 10x as large.

Compression, yes, but "expansion"? Not sure I understand the mechanism at
work there...

BTW, a correction: the files (both JPG and TIF) have only 1 layer. So there's
nothing to "flatten", to the best of my knowledge...

Is there anything I can do to ensure that the "cutout" thing (see original
post) doesn't happen to the recipient of this file?

Thanks,

Andrew Morton

2007-06-12, 6:14 pm

SparkyGuy wrote:
>
> This I know. But where is the additional pic data coming from? The
> original photo is JPG, size ~1.4 MB. When I open that in Photoshop
> and then save as TIF, all of a sudden it's 10x as large.
>
> Compression, yes, but "expansion"? Not sure I understand the
> mechanism at work there...

File size and image size are not the same thing.

When you re-save as a TIFF, you are (most likely) not compressing the image
data in the file.

You want to keep quality=>use a lossless format (e.g. TIFF, psd, raw)
You want small file sizes (e.g. for web pages)=>use jpeg

Andrew

Peter Wollenberg

2007-06-12, 6:14 pm

SparkyGuy <SparkyGuy@mumcrank.ck> wrote:

>Took an outdoor portrait of friends. Camera gives high-res JPG file.
>
>P'shopped it a bit which included selecting the subjects and applying a bit
>of brightness/contrast shifting. Looks good.
>
>Saved it as a TIFF file.
>
>Opened it up in a viewer (Preview, a Mac app) and the area that I selected
>and altered the brightness/contrast of is "cut out". Gone.
>
If you didn't deselect after you were done with the adjustments, you
may have created an alpha channel? It is the purpose of alpha channels
to "cut out" part of an image and replace it by transparency.

Peter

SparkyGuy

2007-06-12, 6:14 pm

> File size and image size are not the same thing.

Yes, I know.

> When you re-save as a TIFF, you are (most likely) not compressing the image
> data in the file.

The original (JPG) file is ~1.3 MB. It grows to ~10 MB when I save it as TIF.

If I go the other way (original is TIF, saving as JPG) I understand the
compression mechanism involved. But going JPG -> TIF, I don't understand
where the additional ~9 MB of picture data is coming from.

> You want to keep quality=>use a lossless format (e.g. TIFF, psd, raw)
> You want small file sizes (e.g. for web pages)=>use jpeg

Yes, I know.

Andrew Morton

2007-06-12, 6:14 pm

SparkyGuy wrote:
>
> Yes, I know.
>
>
> The original (JPG) file is ~1.3 MB. It grows to ~10 MB when I save it
> as TIF.
>
> If I go the other way (original is TIF, saving as JPG) I understand
> the compression mechanism involved. But going JPG -> TIF, I don't
> understand where the additional ~9 MB of picture data is coming from.

There always was 10MB of image data, it's just that it gets squashed into a
1.3MB file with jpeg compression.

Andrew

SparkyGuy

2007-06-12, 6:14 pm

> There always was 10MB of image data, it's just that it gets squashed into a
> 1.3MB file with jpeg compression.
>
> Andrew

Doh!!! (c:

Thanks,

KatWoman

2007-06-12, 6:14 pm

"SparkyGuy" <SparkyGuy@mumcrank.ck> wrote in message
news:0001HW.C293FD0300A12F4FF01826C8@news.sf.sbcglobal.net...
>
> Yes, I know.
>
>
> The original (JPG) file is ~1.3 MB. It grows to ~10 MB when I save it as
> TIF.
>
> If I go the other way (original is TIF, saving as JPG) I understand the
> compression mechanism involved. But going JPG -> TIF, I don't understand
> where the additional ~9 MB of picture data is coming from.
>
>
> Yes, I know.

duh>>>>> the jpg orig is compressed so when you open it it uncompresses
itself and is bigger
(like a zip or rar)
my camera may make a jpg file 1.8 MB on the compact flash card and copied to
hard drive the file size remains 1.8
opened in PS same file is about 14 MB
(RAW and uncompressed same cam makes file about 16 MB)

I have had to flatten and re-save under different file name to make that
alpha layer go away once the file has got saved funny the first time,
opening and flattening the faulty file and re-saving did not work for me

tacit

2007-06-12, 10:15 pm

In article <0001HW.C293E79A009C2AB5F01826C8@news.sf.sbcglobal.net>,
SparkyGuy <SparkyGuy@mumcrank.ck> wrote:

> This I know. But where is the additional pic data coming from? The original
> photo is JPG, size ~1.4 MB. When I open that in Photoshop and then save as
> TIF, all of a sudden it's 10x as large.
>
> Compression, yes, but "expansion"? Not sure I understand the mechanism at
> work there...

When you save a JPEG, the picture is compressed. When you load the JPEG
into Photoshop, or any other program, the compressed information must be
expanded in order to show you the pictures.

You know how Zip files work, right? You compress a file into a Zip
archive, then to use the file you must uncompress it. Same sort of thing.

>BTW, a correction: the files (both JPG and TIF) have only 1 layer. So
there's
>nothing to "flatten", to the best of my knowledge...
>
>Is there anything I can do to ensure that the "cutout" thing (see
original
>post) doesn't happen to the recipient of this file?

What about channels? Do you have any alpha channels in the image? Look
in the Channels palette.

--
Photography, kink, polyamory, shareware, and more: all at
http://www.xeromag.com/franklin.html