Tuesday, 26 July 2016

Back to School - a lesson from new friends.

Hi all,

The last DSO sketch I did, that of the Lagoon Nebula, you may recall I was not totally happy with.  Thing is, I encountered a limitation of the soft pastel dust I use with the Mellish Technique.  The limitation is not being able to lay down a sufficiently dense/brilliant amount of the soft pastel dust.  This is not normally a problem.  However, occasionally there is an object that has a particularly brilliant glow, such as the central hub of the Lagoon Nebula, and also the glowing nebulosity immediately around the Trapezium in the Orion Nebula.  Come to think of it, my last sketch of M42 planted the seed of dissatisfaction as I really was not too happy with the shading density/opacity of the area around the Trapezium.  And this Lagoon Nebula sketch brought it to a head.

A friend of mine, astronomer Dr Renee James, introduced me to a close friend of her's, artist Lee Jamieson.  The correspondence we've shared regarding my work led to Lee suggesting I try powder pigment colours, such as powdered titanium dioxide or zinc oxide.  These pure pigment colours are essentially pure titanium and zinc compounds.  Lee mentioned that these powders would be of a fine grain size than the soft pastel dust, and much more dense in opacity, and not filled with binder material, such as calcium carbonate that is typically used in soft pastels.

This suggestion really caught my attention and imagination.  My initial thinking being that these powders would be like using a sledge hammer to swat a fly if I wasn't careful.  But, these could also be the answer to the brilliance problem I had encountered.

I just had to get my hands on some of this stuff!!!

And thankfully, my local art store is very well stocked, and carries both of these powder pigments.  I picked up a little tub of the titanium dioxide as the zinc dioxide is a little more translucent.

So to test the new powder, I brought up a black and white image of the Lagoon nebula that closely resembled its appearance through a telescope.  I started the sketch as ususal with the pulverised soft pastel.  Once completed, I took to the central areas with the powdered pigment - the results were immediate!

Those areas that I struggled to achieve the desired brilliance now absolutely glow!

Compare with the sketch I did just a few weeks ago.  I was just not able to generate the same brilliance in the right hand lobe and the stripe of material beside the star cluster.

If you decide to use these powdered pigments, be aware that these colours are very brilliant due to their greater opacity compared to powdered soft pastels.  Start very sparingly with it as it is very easy to overdo the intensity of the white.

I can't wait to use this new tool out under the stars next time!



  1. Beautiful work of a stunning nebula. The diffraction spikes on the brighter stars are a nice touch. This past new moon I got a look at the Lagoon using an O-III filter for the first time. It brought out amazing detail, and I immediately decided it was a prime candidate for a sketch. Probably won't be until next Summer after I retire, but I'm definitely going to give it a go. I'm still using graphite pencils on white paper and inverting the image in Photoshop, but I'm also considering Mellish on black paper

  2. Bill, thanks for the comment. The diffraction spikes are a simple device to increase the brilliance of a star without making the star a big ugly blob - the star itself remains a tiny pin prick in size this way.
    Don't forget, this is just a test piece and a sketch of a photo of the Lagoon, and to test the suitability of the titanium oxide to provide that extra lift in brilliance that the soft pastel just is not capable of. But by the same token, this test piece shows how the Mellish Technique can reproduce a photograph. Which is also a great way to become familiar with the technique BEFORE you attempt to do so at the eyepiece. See how the materials respond, how to load the brushes, layering the material in order to correct and also achieve the effect you want, reproducing stars, etc. Something you can do while you are on your journey to retirement! :)


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