New project: camera color profile calculation

jepomat

Gang,

I'm using DNG4PS-2 (0.2.2 - 08.07.200😎 to convert A640 raw files produced with CHDK (GrAnd v148 - 14.08.2007) but the colors thus produced are off.

How do I correct the colors ?

What color profile should I use and how do I use it ?

Cheers !

whim

@jepomat

have you tried using the latest DNG4PS2 ? (DNG4PS-2 0.2.3 Beta build 256)
this beta offers support for A640 (don't know if it does better than 0.2.2 though)
Unfortunately, ArtDen has announced he will stop developing this program, so
if that doesn't improve your results, you might be better off watching the
latest autobuilds - word has it that CHDK will soon support native DNG saving,
check this thread: Save RAW files in DNG format instead of RAW

wim

jepomat

@wim

Thanks for the very quick and useful info. No, I haven't tried 0.2.3 Beta. CHDK support for DNG sounds a great alternative, which I will keep looking for.

Any other ideas or pointers out there ?

Cheers !

whim

About correcting: it seems most(?) people like Adobe Lightroom - me, i hate Adobe
(or rather, bloatware in general) so i use RawTherapee (free, Beta Version released: 2.4beta2 )

wim

PS you are hopefully aware there's an entire board dedicated to RAW & Co. ? RAW Shooting and Processing

vit40

Well, I must admin I don't like Adobe either, but all other raw converters were even worse for me in general, so I'm using ACR ...

Are there currently any software, besides ACR and Lightroom, that support dng color profiles ?

whim

Well, since a DNG is basically a raw with color profile, there wouldn't be much point for a
program to be able to read DNG without supporting it's color profile, would it ?
So my guess would be the answer to your Q is: all programs that can open them 😁
Don't quote me on that though, i only occasionally use raw ... but for my cams
DNG4PS2 and RT have worked OK.

wim

vit40

There are two dng specifications. Old one supported only color matrix (one or two) and simple matrix transformation from sensor color space to destination color space (sRGB, Adobe RGB etc).

New specification supports usage of ''real''color profiles in form of lookup tables, and also introduced forward matrices. This way, it's possible to get the same colors as from in-camera jpeg, which isn't possible with simple matrix color transformation

I'm asking about the second one

holgi09

Hello,
here is a .CRW and a .jpg from the Ixus 75.
100CANON.zip - 8.57MB

Is it good enough to calculate a camera profile for the Ixus 75?

ewavr

holgi09
Hello,
.CRW and a .jpg from the Ixus 75.
Is it good enough to calculate a camera profile for the Ixus 75?

So, because ArtDen stopped DNG4PS2 support, try it yourself 😉
In version 0.2.3-beta16 copy IXUS70 settings to IXUS75 (the same matrix size).
Then try to calculate color profile from your images using "calculate color matrix" tool.
My result for color matrix 1 is:
0.689833 -0.198299 -0.101299 -0.164267 0.667466 0.074132 -0.036515 0.123872 0.248498

But I am not color expert, somebody can do this work better...

edit: Oops, DNG4PS2 cannot load new camera profile after program restart. Maybe this a big bug. :'(

holgi09

Hello ewavr,
thanks for your reply...
but ist doesn't work.
Can anybody else describe the steps to calculate an camera profile?
With the integration in CHDK to save raws as dng's it is more important to have a profile for the Camera. In that case, this feature can be implemented for my camera in the autobuild...

ewavr

holgi09
thanks for your reply...
but ist doesn't work.

Because colors are bad with my matrix? Indeed, I am not guru in color calibration :'(

holgi09

Ok, step by step.
I open DNG4PS2, then i click on settings (DNG4PS2 is version 0.2.3 Beta build 256).
Then i choose the register "camera options", select IXUS 70 in the Camera list.
Then i select "copy" and confirm the popupwindow,
In the field "color matrix #1" i select the Illuminant "daylight" and copy your values in the "Matrix" field.
Then i choose the register "camera types" an select in the field "3152x2340" the new entry.
Then i select my .crw and .jpg files and click "convert".

The result is an error "Can't find camera profile for this file".
and no .dng file is created. :'(

ewavr

Well, here is my actions:

1. press "settings" button -> choose camera options tab.
2. in "camera" list choose IXUS70. Click "copy" button, in confirmation dialog click "yes"
3. Change camera name from "Copy of Canon DIGITAL IXUS 70" to "Canon DIGITAL IXUS 75" and short name from "IXUS 70" to "IXUS 75"
4. Scroll down window and enter new color matrix.
5. Press OK button, you can see at end of camera list "IXUS75"
6. If no JPEG files in corversion folder, select "IXUS75" for images with 3152x2340.
7. Start conversion.

I tried this many times with your images, it works.
Unfortunately, DNG4PS2 cannot save new camera profile, you must enter it manually every time after DNG4PS2 start.

holgi09

Ok, now it works! :😀

My mistake was the selection of the Camera Type in the camera type list.
Without that selection the DNG files are converted and look good!

Thank you for your help.

thearrow

A590IS Color Chart:

Test pics later if you need them.

Thanks!

ewavr

thearrow
A590IS Color Chart:

6 Set focus to infinity

In your image subject distance was 0.5m.
However, calculated matrix (0.74257 -0.21290 -0.12061 -0.13795 0.62377 0.04344 0.03732 0.04839 0.23131) is very similar to old one (647380 -169846 -115337 -11566 451223 13279 62541 54140 16114😎, used for CHDK DNG shooting (maybe someone can calulate it better?).
Also adjusted cropping settings (ACTIVE_AREA_Y1=12, ACTIVE_AREA_Y2=247😎.

thearrow

I didn't realize chdk had a built-in option for dng output........ 😳

Coeluh

thearrow
I didn't realize chdk had a built-in option for dng output........ 😳

Huh WHere?

whim

@Coeluh

Main Menu -> Raw Parameters -> DNG Format

wim

Coeluh

whim
@Coeluh

Main Menu -> Raw Parameters -> DNG Format

wim

I had to create a badpixel.bin. But it says i've like 8211 bad pixels. Is that a huge amount? And I see that i'm getting more noise than ever. Is the badpixel removal thing a good thing?

« Previous Page Next Page »