Is This Oversaturated?

[Koshua]

DSC-18 by Joshua Kemmer, on Flickr

I'm going to be making a print of this, and I know colors appear less saturated on a print. Did I go overboard for digital too though?

 

[unpopular]

yes. to the point that you're loosing detail.

also, colors don't so much appear less saturated in print, it that you have fewer colors to choose from. Simply boosting up the saturation isn't advisable as all you end up doing is pushing the color further out of gamut and hoping that the RIP will have a better idea of what you have in mind.

 

[Koshua]

yes. to the point that you're loosing detail.

also, colors don't so much appear less saturated in print, it that you have fewer colors to choose from. Simply boosting up the saturation isn't advisable as all you end up doing is pushing the color further out of gamut and hoping that the RIP will have a better idea of what you have in mind.

I have a tendency to do that, but I don't understand why I can't determine if it's way over-saturated or not if I've been editing pictures with the same subject material for a while. If it's just a few pictures, I'm fine, but when it's a ton, I always over-saturate.

Thanks for the info! I'll research some more on proofing.

 

[unpopular]

If in photoshop and you have a device profile, under view there are your soft proofing options. I don't know why more photographers don't use this feature.

Watch your histogram, make sure you're not clipping when adjusting saturation, and make only local adjustments where needed, rather than applying saturation globally. Adjusting saturation in LAB mode also is a good practice.

Be sure to be editing in 16-bit if you're shooting raw.

 

[Tim Tucker]

You will find it easier to see and judge saturation if you learn what it is first. Even in this thread there is already possible confusion between saturation and brightness.

Daylight is what we call 'white light', a mix of all the wavelengths of light together and in roughly equal values. When this light hits a surface the surface absorbs some of these wavelengths and reflects the rest. It is this mix of different wavelengths of light that produces the colour we see. Everything in nature reflects a combination of different wavelengths, nothing only reflects just on or a narrow band of wavelengths. For that you need to look at transmitted light, or light that has passed through an object as this filters light, or in the case of a rainbow, splits the light.

There are far to many colours, or combinations of wavelengths to name. So we tend to name the significant ones only such as specific pigments that can be mixed to produce ranges of other colours. All colours though are described by the HSL (or HSV, HSB) colour model.

A Hue is a colour of a single wavelength. Objects do not reflect all light equally they tend to reflect light of certain wavelengths more than others. When we talk of an objects colour we describe it in terms of its Hue, or the most dominant wavelength that makes up the colour:

The saturation of a colour is the ratio of the hue that's dominant in the colour to the other hues that are in the colour:

Notice that when you saturate colour the band of wavelengths included in that colour gets smaller and the ratio of the dominant hue increases. If you de-saturate completely then you make it so all wavelengths are included and equal and the colour becomes grey, (this is one way of de-saturating a colour and the best way to imagine it in an RGB workspace).

Luminosity, (Brightness, Value) is that amount of light the object reflects. Notice in the graph above that the colour is not brighter, it reflects the same total amount of light and it is just concentrated into a smaller band of wavelengths. To increase the brightness then you increase the amount of light reflected. Bright colours are not saturated colour, and neither is all saturated colour bright:

It is very important to remember that the RGB workspace on you computer monitor does not display all wavelengths of light. it displays a limited gamut of colour by mixing three primaries only. Here are the colours as they are represented in an RGB workspace, notice it's the brighter colour that clips and not the saturated one:

EDIT: The colours shown in the above graphs don't actually clip at the brightness shown, but they would if you increased brightness.

Now in certain circumstances where you over-saturate a specific colour that can only be displayed through one channel (red for example) then you find clipping because of over-brightness of that channel. That is what clipping is, over-brightness, and it can also be software clipping of over-bright out of gamut colours.

Back to the image. The left half is original and the right is just my colour correction. I have not changed the brightness of the image, clipping was probably down to editing in the limited sRGB workspace:

Please look carefully at both sides, more than a casual glance, and you will notice a number of things:

1) Which side actually appears more colourful, the saturated or less saturated side? The main reason is that colour works through contrast between colours, and for contrast you need variety. Saturation reduces that variety by thinning the colours that are composed of multiple wavelengths. There is another reason, and that is WB. In a scene like this there is no single constant colour temperature, it is lit by light of varying colour temperature. Therefore a lot of the shadows and distant haze will have a slight colour cast. What happens is that your neutral tones are no longer neutral but take on the cast as a dominant hue. Which you then pull forward with saturation because you make it more dominant.

2) Which side has more detail and texture in the foreground rocks? Detail and texture is not all about luminosity and contrast, you can separate tones with colour as well, saturation reduces this difference.

3) Which side has more contrast? Remember I have not changed this at all, only the colour balance. Contrast exists between different colours as well as different luminosities, removing this difference also effects your perception of contrast and sharpness.

Hopefully I have demonstrated the visual difference saturation makes in an image, and how it differs to brightness. Here the image is again, but this time with an equal reduction in brightness to both sides so no channels are clipped. You will see the same differences as noted above:

 

[Taveuni]

Tim, what an excellent post.
Very informative and well written, I got a lot from that.

 

[weepete]

I think that takes the nomination for answer of the month. Great job on probably one of the best answers I've ever seen to this question.

 

[Koshua]

Thank you so much Tim! I've never seen anyone take the time to write something like that out for someone over a messageboard, plus you even edited my photo for the visual aid. Outstanding. I'll think about this every time I go for the saturation bar from now on!

Love your website by the way, those photos are unbelievable.