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Lessons Learned: Dealing with Color

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#1 rolandlinda3

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Posted 25 June 2009 - 04:58 PM

When doing deep sky objects that have color (nebula, planetaries, some galaxies primarily) it can get real interesting and complex in a hurry. We sketch about half the time with astro video tools, which means we are often confronted with quite an array of color along with about 3 or 4 times the star field that one sees with a straight EP. However, for anyone observing a bright object and a larger amount of aperture, the situation with color still presents itself, albeit in subdued tones.

I thought a couple comments might be interesting, and would suggest to sketchers to try either astro video or a large aperture scope with EPs to see if you find some of the same things. For those that have done deep sky objects live and in color, you may have some comments with your experience. The assumption in what follows is that one starts with a black piece of sketch paper. I don't think I would ever attempt this with white paper.

1. Color is not simple. While at first clance many objects have reds and/or pinks, it does not take too long studying to find that the number of hues among the reds and pinks is not so straight forward. Add an objective area that has purples, greens, and blues...then the sketch time becomes a challenge because its like another dimension added to the light density of a region. Add to this some very sharp or prominent dark lanes, now its a full-blooded complex object staring you in the face. So when we see an object in color, the first step past the first glance is to agree to continue although it is apparent that the complexity is beyond our abilities.

2. We do what we know to do first: lay down the anchor stars and the single or few areas that have the brightest core of nebulosity of density that are not stars. We generally do this with a soft pencil unless we are using all pastels; then we use a pastel pencil. Selecting the star field is not straight forward since we select stars that also help us locate key parts of the color areas or dark lanes we want to capture. So it might be the brightest stars but sometimes it is star pairs or apparent asterisms--anything that is not too hard to re-locate when we lose our bearings when trying to get color boundaries placed correctly. Getting lost is real easy without some good reference points established over the whole region. On a big nebula or galaxy, I probably have to locate 30 stars or so.

3. We pick the dominant color, which is a subjective choice to identify the most prominent shade of whatever color is in an obvious part of the nebula. Then we lightly outline and lightly fill that area with relative density in the region we are addressing. If it is a galaxy with color, it is different. We use white pastel to locate the arm locations relative to the stars we have already laid down then add (typically) a pink or yellow for the most prominent color areas. For all objects, it takes quite a long time to do these first steps with the dominant colors or white. Invariably, the pastel covers some of the weaker stars we identified, so we touch them again. Or, we have to add stars because they identify locations of a color boundary, dark lane, fuzzy in a galaxy arm, etc.

4. As this process develops, we have changed colors as we work ourselves over the region as it is necessary. But we are still using the most dominant colors. I deliberately do not pay attention to color changes and transitions at this point. For complex nebula and galaxies, we most often get this far with 4 or 5 colors (white, couple reds/pinks, and maybe a purple, green, or blue, or yellow).

5. If things have gone well so far, blacks come in really handy at this point because we accent prominent boundaries of dark lanes and larger black areas because they help place us in the object (keep us from getting lost) and they help us see the overall contrast and color changes properly. We purposely do this after the initial lay down of primary colors since we are using black paper.

6. The next steps are working with a finger, blending stick, and additional colors. This begins the work on transitions of color in the object and adds heretofore unidentified hues. We have done this part with a small set of pastels rather than a huge set, which is cumbersome. The small or medium set has enough choices so with white and greys you can blend to get what you want. If the object is really outrageously full of varied colors, then it does help to have some good choices. Observing and re-observing/studying parts of the object at this point begin to get in a groove: we begin to see refinements of not only color, but also shapes of color or dark areas in more detail in addition to color density. Density is a bit of a challenge, because I find it has to be adjusted as we develop the color sketch. With astro video, which essentially triples the aperture of the scope and adds color, density changes over the object get real interesting quickly. So working with a blending stick takes some time.

7. High density areas in the end almost always have to be strengthened. The eye/brain is pretty good at identifying detail, but as we address detail, we seem to accentuate a bit too much. Then we stand back and find that the dense color areas on the monitor need more emphasis to be in proper balance with the weakest parts of the objects.

8. As the sketch time draws to a close, there is an alternative review that begins to happen. We stand back and correct over-all missed densities of color or hues. We also see missing detail in particular areas and go correct those. This can go on for quite awhile until we find ourselves correcting corrections. This is the point where we often say....that's enough, we have reached our limits.

Last, this same approach helps us for moon sets, moon rises, moon views with terrestrial contrast, where a host of colors and changing light conditions leads to the same complexities as deep sky objects.

In the end, love the crispness of black and white, but color does add an exciting although complex dimension for us. Try it if you have not.

#2 frank5817

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Posted 25 June 2009 - 05:32 PM

Roland,

I must agree with you concerning the use of color. It can be challenging and adds a whole new dimension to sketching. It does require some practice and is often subtle unless you are using color video as you do so masterfully well.
You lessons are well spelled out. :cool:

Frank :)

#3 CarlosEH

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Posted 26 June 2009 - 06:50 PM

Roland,

Thank you for describing your technique in clear steps. This is helpful for all observers.

Carlos

#4 rodelaet

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Posted 28 June 2009 - 08:16 AM

Roland,

If color sketching is too complex:
Would you be interested in separating the colors from your monitor?
The procedure is simple at the sketch, but more complex at the desk.
I guess that your monitor can have its colors adjusted in a way that only one of the RGB's comes through. That way, you can concentrate on one color at the time.
You could create 4 sketches in B/W: one B/W, a green , a blue and a red one. Then you can color each sketch and merge together, both coloring and merging with the computer.

#5 rolandlinda3

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Posted 28 June 2009 - 02:00 PM

Thanks all for the comments.

Rony, yes one could do each primary color first and combine, but color definition and density also involve whites and greys, so the additive effect, by the time one plays with it, would be quite a bit more dense for some parts of typical objects and would get complicated to correct. Also, the eyes are really good at interpretting density and hue changes over a spatial area because of the way we were created to see and interpret. It is quite a process that occurs and sketching the colors at one sitting take advantage of our quick abilities to interpret changes. To me, its more a question of getting the interpretation on the paper that is not easy (I see what want to do but can't quite get there), but thank goodness for blending stumps and using them to apply as well smooth color. I am getting quicker but the learning process will probably take a life time. It sure is fun learning!!

I prefer, also, to stay away from using computer techniques as a substitute for my steps of creating the scene. That is just me, of course, since many prefer the opposite. I limit the computer work to scanning my failings or my strengths.

#6 markseibold

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Posted 30 June 2009 - 01:39 PM

Roland

An excellent post with discussions of color interpretations. :bow: :bow: :bow: Everyone can and should read your techniques here as there is much to learn from this as a tutorial for both observing, color interpretation, and sketching. Also great input by others here too.

Although I know many use computer software today, I tend to agree with you about the traditional methods of hand sketching and rendering color. It is amazing how you are using the video to see through. I was entertained to see Rony sugggest making several duplicate sketches in various RGB then merging them. Man, that would be an exercise! :question: [For your serious technical artists eyes only] :cool: It conjurs up the photo technique of HDR photography- The camera takes three exposures of varying over-under-and one proper exposed, then merges all three in a software program. It has become popular with daylight landscape photographers to produce surreal and stunning images with details in the shadows and highlights that could not otherwise be attained in the old single exposure method; now some camera brands are building it as an automatic option into the camera. Have you or others heard of this? I suppose that is another topic for another forum. Or could this apply to astro imaging too?

I always enjoy your posts with the excellent texts on explaining your techniques.

Thanks again for posting this one,

Mark

#7 Shannon s

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Posted 30 June 2009 - 03:45 PM

Can you guys see colors through the Ep's on DSO's????? I can only see color on planets. Maybe a tinge of light green in M 42.

#8 rolandlinda3

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Posted 01 July 2009 - 01:13 PM

Shannon, you are correct, but I use an astrovideo camera in place of an eye piece. The color CCD chip takes the live (or almost live) image and puts it on a high resolution screen, where I can study and sketch the object. You could see color in some objects with a lot of aperture (typically over 20 inches) but nothing compared to using one of these little video cameras. We went this way rather than get expensive EPs and buy lots of aperture. In addition, my wife and I have both seeing limitations and some physical issues, so this provides a way to sit together and study/sketch without sacrificing the ability to really observe in detail. If interested, you can go to the video forum and see some discussion among the users of this particular video camera as well as some B&W versions.

#9 Shannon s

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Posted 01 July 2009 - 04:05 PM

Thanks Roland. I'll check that out.






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