Red Rhododendron... why are some flowers so difficult?

Thanks …that was a nasty little spot. I was so focused on the flowers I didn’t really notice it


…in the end I just did a quick and dirty retouch to hide it…

Similar issue from a year ago…

Maybe that’s what you would like to reach?
IMG_7089_02.CR2.xmp (8.8 KB)

1 Like

The problem with vibrant flowers is they are often out of gamut. Our cameras capture them just fine, but monitors, most of which can only display srgb, can’t display their full saturation. When colours are out of gamut, they get shunted back in gamut for display. This can either lead to clumpiness/posterization and loss of fine detail, or hue shift such as red towards Magenta. The only ideal solution is monitors with bigger gamuts. Short of that, if you want to retain detail you need to desaturate, but then they look dull. In the other thread @priort linked to above I found the best way to deal with them was to avoid boosting exposure much, or at all. Watch the waveform and ensure you don’t push the red channel above clipping.

The gamut compression slide is a nice assist as well… or can be…playing with that and selective tonal chroma, saturation and brilliance tweaking in rgb CB usually give something pleasing at least if not accurate…

Throwing a LUT on is another way to see if you can massage the color… some nice greens and reds I think with these ones

sunny_rich.zip (116.4 KB)

PhotoFlow + G’MIC

Take 1

Take 2 (looks better with darker background - by default, the forum’s is white)

2 Likes

with Art

3 Likes

ART
IMG_7089.CR2_red.arp (12.4 KB)

Darktable
IMG_7089.CR2.xmp (13.7 KB)

1 Like

It’s probably not the camera but the output medium (display). If you have a highly saturated red hue with a high dynamic range in luminosity it is nearly impossible to get a realistic representation on an 8 bit sRGB display.

Thanks again all. The WB was definitely off - it seems to have guessed 4800K. My guess is at the sunniest end of overcast - 6500K.

Some of the renderings above seem to be heading too much into yellow/orange for my taste which makes the flowers look like they are ‘going over’.

I hadn’t spotted the little bright patch - I guess this must be the sky reflecting from the edge of the waxy leaf because there is nothing bright behind the plant.

I take the point about the higher gamut monitors and limitations of sRGB but I like to share my better photos online so I guess I will need to live with ‘average’ display equipment and either accept dull red flowers or stick to photographing the less tricky ones. Sometimes I get things printed too… which is probably even worse for gamut.

My try.


IMG_7089.CR2.xmp (8.5 KB)

1 Like

there are two problems. the input device transform and the limited output gamut (srgb). if you look at this vkdt screengrab:

you’ll see the default processing using the D65 dng matrix and in the top right corner you’ll observe that much of the red is outside the smallest shaded triangle there (rec709/srgb), although within rec2020.

if i use an estimated ssf profile, i get this (at 6000k wb):


which still shows reds outside of gamut, but not nearly as pronounced as before.

take the images as illustrations with a good grain of salt: they are colour managed for my screen (not yours). so they will give you a rough idea, but the hard data is in the plot (top right corner).

3 Likes

Take 1 without converting to sRGB standard (rec2020 linear → rec2020 standard[?]). The colours are darker and have been shifted further but reveal more detail in the flowers. Zoom for better viewing and contrast.

[?] sRGB curve?

Combining all that, we have
Take 3 – zoom to appreciate

1 Like

I had another go myself… looking at the real thing through the window. I couldn’t quite live with the 6500K white balance - it still makes the flower look too orange so played with it a bit more… 5500 seemed too blue so I spit the difference and 6000K seems (to my eyes) to be not terrible.

I think my main other changes are -0.45EV exposure, a color balance RGB preset based on ‘add basic colorfulness’ but with everything halved and then pushed global saturation up by 7.3%.

The brighter parts of the petals are trigger a clipping warning with ‘any RGB channel’. If I set the warning to ‘full gamut’ then the whole thing becomes a mess (which seems to be saturation) but I’ll live with it.

The real thing still looks a lot better :slight_smile:

2 Likes

Hi Halina3000. I have encountered the same problem. Red flowers can be problematic. Many digital camera sensors have difficulty detecting subtleties at the red end of the spectrum. I’ve never been able to get truly satisfactory results when photographing red flowers. I end up having to make do with less than perfect. Some tweaking in Darktable or similar can sometimes help slightly, but unfortunately, there’s nothing much that can be done to obtain faithful realism when colour information is actually missing, due to the camera sensor’s limitations.

1 Like

I found that the red channel gets blown easily with red flowers, and that makes editing afterwards difficult.

In addition, there may be a bit of UV in many flower colours, which the camera can detect (as blue), but we don’t.

1 Like

The gamut compression slider in CC module can help and the colorfulness sliders also are nice to apply to help tweak those gamut/saturation issues

1 Like

Here’s my attempt. Tweaking color calibration to bring the blooms in line helped a lot


IMG_7089.CR2.xmp (11.2 KB)

1 Like

Edited in Gimp.
I lowered the exposure by about one stop and lifted the green channel using the red channel in brighten mode, then i blended the two layers in luminosity mode.
Hard to get a good contrast without blow out the reds and keep colors in gamut.

My fun in GIMP

1 Like