Am 21.03.2011 00:07, schrieb Trevor G Quayle:

> Hopefully this is much better.

Hmm, it *is* brighter but I'm not so sure about *better*.
You have some quite distracting color banding on the rear wall and you 
are completely loosing the dim movie theater feeling here.
The main problems within your previous version seems to me: almost 50% 
of the pixels are pitch black (rgb 0,0,0) and plain black pixels is 
something that should (for photorealistic images) be avoided like the 
plague.
Even within this brighter version are almost 25% pixels just black (the 
upper walls, ceiling, the pylons, the speakers and parts below the seats).
On the over hand you are not using the full dynamic range which makes it 
look somehow flat. There is no need to make it overall brighter but 
there is some need for bright spots.


> I tried to do some calibration with my monitor.

See my 'Calibration' post, it might help.

-Ive

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Ive <ive### [at] lilysoftorg> wrote:
> You have some quite distracting color banding on the rear wall and you

I've noticed this.  This looks like it is coming from the very dim 'fill'
lighting I am using along part of the projector beam.  The light intensity is
right near the bottom of the colour depth so it tends to get stepped.  I tried
it with HDR image type output and the banding disappears (converting the HDR
back to JPG or PNG reintroduces it).  I may either have to adjust how I approach
this light, adjust the texturing to better mask it, or just get rid of it
completely.

> The main problems within your previous version seems to me: almost 50%
> of the pixels are pitch black (rgb 0,0,0) and plain black pixels is
> something that should (for photorealistic images) be avoided like the
> plague.
> Even within this brighter version are almost 25% pixels just black (the
> upper walls, ceiling, the pylons, the speakers and parts below the seats).

There is a very good reason for this:  durrently those particular parts have a
'rgb 0' pigment attached.


> > I tried to do some calibration with my monitor.
>
> See my 'Calibration' post, it might help.
>
> -Ive

Helps a little.  I think the big problem before was my monitor gamma was bumped
way too high.  However the brightness setting is something I could not find a
lot of information on previously.  When calibrating before and fixing the gamma,
I had bumped this right down (0%), but using your posting I have it somewhat
higher (40%).


-tgq

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Am 21.03.2011 14:37, schrieb Trevor G Quayle:
> Ive<ive### [at] lilysoftorg>  wrote:
>> You have some quite distracting color banding on the rear wall and you
>
> I've noticed this.  This looks like it is coming from the very dim 'fill'
> lighting I am using along part of the projector beam.  The light intensity is
> right near the bottom of the colour depth so it tends to get stepped.  I tried
> it with HDR image type output and the banding disappears (converting the HDR
> back to JPG or PNG reintroduces it).  I may either have to adjust how I approach
> this light, adjust the texturing to better mask it, or just get rid of it
> completely.

For a PNG file without colour banding, you may want to use dithered 
output (+TH). (You can also try it for JPG, though I'm not sure whether 
that will improve results.)

Alternatively, you can convert the HDR or EXR output using Ive's "IC" 
("Image Converter", see http://www.lilysoft.org/IC/ic_index.htm), which 
does a much better job at avoiding color banding than most other image 
manipulation/conversion software.

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clipka <ano### [at] anonymousorg> wrote:
> Am 21.03.2011 14:37, schrieb Trevor G Quayle:
> > Ive<ive### [at] lilysoftorg>  wrote:
> >> You have some quite distracting color banding on the rear wall and you
> >
> > I've noticed this.  This looks like it is coming from the very dim 'fill'
> > lighting I am using along part of the projector beam.  The light intensity is
> > right near the bottom of the colour depth so it tends to get stepped.  I tried
> > it with HDR image type output and the banding disappears (converting the HDR
> > back to JPG or PNG reintroduces it).  I may either have to adjust how I approach
> > this light, adjust the texturing to better mask it, or just get rid of it
> > completely.
>
> For a PNG file without colour banding, you may want to use dithered
> output (+TH). (You can also try it for JPG, though I'm not sure whether
> that will improve results.)
>
> Alternatively, you can convert the HDR or EXR output using Ive's "IC"
> ("Image Converter", see http://www.lilysoft.org/IC/ic_index.htm), which
> does a much better job at avoiding color banding than most other image
> manipulation/conversion software.

I tried the converter, the banding is still there.  I may have a look at the
dithering.

-tgq

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Am 21.03.2011 16:25, schrieb Trevor G Quayle:
>> Alternatively, you can convert the HDR or EXR output using Ive's "IC"
>> ("Image Converter", see http://www.lilysoft.org/IC/ic_index.htm), which
>> does a much better job at avoiding color banding than most other image
>> manipulation/conversion software.
>
> I tried the converter, the banding is still there.

Hum? Actually I can't believe that but it might be my own fault as I 
never managed it to write a decent documentation.
In case you use IC for converting some HDR format to PNG it will store 
the PNG in 16bps format (to avoid unnecessary loss of information) and 
the banding will be introduced again when you use other viewing software.
So you have to reduce the color depth before you actually save the image 
file by using the menu item
Image -> Mode -> RGB 8bps
- and make sure within the Options menu that dithering is actually enabled.

-Ive

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Ive <ive### [at] lilysoftorg> wrote:
> Am 21.03.2011 16:25, schrieb Trevor G Quayle:
> >> Alternatively, you can convert the HDR or EXR output using Ive's "IC"
> >> ("Image Converter", see http://www.lilysoft.org/IC/ic_index.htm), which
> >> does a much better job at avoiding color banding than most other image
> >> manipulation/conversion software.
> >
> > I tried the converter, the banding is still there.
>
> Hum? Actually I can't believe that but it might be my own fault as I
> never managed it to write a decent documentation.
> In case you use IC for converting some HDR format to PNG it will store
> the PNG in 16bps format (to avoid unnecessary loss of information) and
> the banding will be introduced again when you use other viewing software.
> So you have to reduce the color depth before you actually save the image
> file by using the menu item
> Image -> Mode -> RGB 8bps
> - and make sure within the Options menu that dithering is actually enabled.
>
> -Ive

Maybe a little RTFM on my part...

I do get it to work now.  The problem was I didn't set to 8bit, but also I was
saving direct to jpg.  I assume then that the dithering doesn't apply to jpg
saving?


-tgq

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Am 21.03.2011 17:55, schrieb Trevor G Quayle:
I assume then that the dithering doesn't apply to jpg
saving?

Dithering works also with jpeg output but as jpeg is always lossy
and most of all the RGB -> YCbCr (the color space internal used by jpeg) 
  transformation is already lossy it might happen the the dithered color 
falls exactly into a gap produced by rounding errors of the lossy color 
space transformation, err, if you know what I mean, I'm not very good in 
explaining such things.
First try it with the option chroma-subsampling (within the 'Save JPEG 
Options' dialog) DISABLED and a quite high quality setting (lets say 
95%) if this doesn't help you can try to change the exposure value (just 
some barely visible amount increased or decreased) within the 
Tonemapping dialog so the dithered colors might miss the 'gaps'.

-Ive

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Ive <ive### [at] lilysoftorg> wrote:
> Am 21.03.2011 17:55, schrieb Trevor G Quayle:
> I assume then that the dithering doesn't apply to jpg
> saving?
>
> Dithering works also with jpeg output but as jpeg is always lossy
> and most of all the RGB -> YCbCr (the color space internal used by jpeg)
>   transformation is already lossy it might happen the the dithered color
> falls exactly into a gap produced by rounding errors of the lossy color
> space transformation, err, if you know what I mean, I'm not very good in
> explaining such things.
> First try it with the option chroma-subsampling (within the 'Save JPEG
> Options' dialog) DISABLED and a quite high quality setting (lets say
> 95%) if this doesn't help you can try to change the exposure value (just
> some barely visible amount increased or decreased) within the
> Tonemapping dialog so the dithered colors might miss the 'gaps'.
>
> -Ive

It had to do with the quality settings for JPG.  Was set to 90%, setting to 100%
works fine.  I hadn't found where the settings were before, the Format Option
button was a bit inconspicuous I guess.

Very nice little program.

-tgq

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"Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
> "Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
> > clipka <ano### [at] anonymousorg> wrote:
> > > Am 20.03.2011 09:04, schrieb Thomas de Groot:
> > >
> > > > I don't see anything... Gamma?
> > >
> > > Looks more like an absolute brightness issue to me.
> >
> > I have been having difficulty calibrating my home monitor, so this image was
> > visible to me at my previous settings.
> > I have tried to do some calibration, and I think I have my monitor gamma setting
> > way too high.
> >
> > I'm going to have to try to figure some of this out, but it is difficult to find
> > a difinite source to help me get the settings correct.
> >
> > -tgq
>
> Hopefully this is much better.  I tried to do some calibration with my monitor.
>
> -tgq

Next update.  I moved our guy to a different movie, changed the seat texture, I
changed all wall and roof textures to the same and added a light to the booth as
well.

-tgq

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Attachments:
Download 'matineescene 5.jpg' (193 KB)

Preview of image 'matineescene 5.jpg'

> Next update.  I moved our guy to a different movie, changed the seat texture, I
> changed all wall and roof textures to the same and added a light to the booth as
> well.

Looking great!

If I were to offer one suggestion, it would be that all the movie theaters I've
been in have a glass window in the projection booth, and the movie, a bit out of
focus, can be seen projected on (or though I guess) the window.

> -tgq

Cheers,
Edouard.

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