Smooth watercolour washes (without the stress!)

By Grover Koelpin 25 comments

Usually, painting in the detailed way that I do, I don’t have the need to paint a large area of a really smooth wash effect. But here I wanted to paint a clear blue sky to make my magnolia stand out, so I thought I’d show you how to do it – without the stress. Firstly I need to use a brush much bigger than my normal ones and able to hold lots of paint. This is a ‘mop’ style round brush, made of synthetic hairs. This size of brush will paint areas of wash up to about size – 12 by 16 inches or 30 x 40 cm. It’s about 3cm/ I inch long, and just under a cm (a 3rd of an inch) wide. Secondly I paint onto textured cold pressed paper (sometimes confusingly called NOT paper – as in ‘not’ hotpressed). Normally I work on hotpressed, very smooth watercolour paper This allows me to paint really crisp edges which is perfect for detail. But, the textured surface of does have a purpose, and that purpose is to evenly distribute the watercolour paint over the paper when we lay down a wash.
Here you can see the difference between a wash on smooth, hot pressed paper and textured, cold pressed paper.
As I’m also wanting to paint detail in my picture, , with the magnolia, I will loose some definition with my details so it’s going to be a trade off, but I really have to use the textured paper to get the smooth effect over this large area. Because I’ll be working with wet paint, in a quick way, I must make sure I mask off the flower here so that I can achieve a nice crisp edge to it. So I draw the outline edge of it only and fill it in with masking fluid. In order to get a smooth, even coverage over a large area, we must make sure that we don’t create hard line edges where the paint dries as we are re-loading our brush. It’s for this reason we need to mix up enough paint to cover the whole area at once, and I’ve used this plate to mix on so I have plenty of room for the paint. So we need to move quickly and we usually think we have no room for error as it’s hard to rectify any mistakes. This is what can prove pretty stressful when looking to achieve a really smooth finish with watercolor. But I find the best way to safeguard against getting any unwanted hard line edges is to work in layers. I want to aim for at least 4 layers in total – the more layers, the more scope there is for being able to correct any hard line edges that might appear. So because I want 4 layers, I aim to create a mix which is at least 4 times lighter than I want the final result to be. Knowledge of this comes with practice but you can test your mix in your sketchbook first. Working on dry paper, I apply the mix with a back and forth wash motion as smoothly and evenly as I can, moving quickly with my brush and taking care not to let areas dry out as I re-load my brush. Note that I work with the paper flat. This is because I am aiming for a completely even coverage. If you wanted a gradient effect with the paint darker on one side than the other then you could angle your paper at about 45% with the edge that you want to be darkest at the bottom, so that the paint will pool there and appear darker as a result. Ideally you want to work methodically so that you only ever have one drying edge to concern yourself with at one time! As you’ll see here, I did NOT do that with this first layer and here I have 2 edges that are drying at once which was really tricky to manage. I’ll just speed this up to show you. I ended up getting a small hard line edge, which I then made much worse by trying to work into it whilst it was still wet. Adding more water to it just made it ‘bloom’ out and create an effect I really didn’t want. If you did this you might be concerned that your smooth sky was ruined – and it would be if you wanted your sky to be this pale and had hoped to apply it in one layer. But you’ll see how, through applying more layers we can get rid of that hard line edge effortlessly. Crucially I wait until the paper is fully dry FULLY dry before I apply the next layer. Then I apply layer 2 and let THAT dry. Then I apply layer 3 and let that dry. Look how that hard line edge I’d made has naturally disappeared. If you created a hard line edge at this later stage, you could still rectify it by diluting your wash right down. and adding a couple more layers. Because those next layers would be much more watery, they wouldn’t take the area too dark but would soften the hard line edge. And finally I apply layer 4. Once that’s dry I then peel off the masking fluid and after neatening up a few of my flower edges with the same blue paint and a tiny brush, I carry on and paint the rest of the flower as normal. So, why not try working in layers with YOUR washes, letting each layer dry in between, for smooth and stress-free watercolour effects. The full step-by-step tutorial of this whole magnolia flower in full detail is available via my online school.



Jun 6, 2015, 4:17 pm Reply

Great video! Thanks!

Connie Faye

Jun 6, 2015, 5:10 pm Reply

this is not necessarily true, if you use a large flat brush and wet your papers first, and work wet in wet you'll come away with a very nice flat wash. And it's not necessarily true that you need to use cold press to get a nice even flat wash, I almost exclusively on Hot Press.

Buttered Lumps

Jun 6, 2015, 5:16 pm Reply

I actually prefer the cold press for all my paintings, i just love the texture and the smoothness of larger area paintings and how much pigment it can hold compared to smoother paper. Sometimes i don't mind the smoother paper, but its allot more bothersome to use them than to use cold press rough papers for me.

Andre van Wyk

Jun 6, 2015, 12:00 pm Reply

Thank you Anna. I take it that big round brush is a #6 Rosemary 304?


Jun 6, 2015, 12:31 pm Reply

Great tutorial ! Your art is stunning…and these magnolias are beautiful!!

Zubeyde Parlak

Jun 6, 2015, 1:28 pm Reply

Anna,tesekkurler,cok guzel,cok yararli oldu.:)

Doreen Christie

Jun 6, 2015, 2:13 am Reply

smooth watercolour washes, thank you quite interesting concept.


Oct 10, 2015, 9:08 pm Reply

Helpful! Thank you!

Cheryl Scrivens

Feb 2, 2016, 4:36 pm Reply

Sandy Allnock referred me to see how you do your background washes. I've already signed up for watercolor classes and am eager to start one soon. Thank you for a wonderful video! Your amazing is exquisite!

Yvonne Sun

Sep 9, 2016, 8:40 am Reply

I have been struggling with that drying edge for a while now, thanks for the vid!

Jose Azofeifa

Jan 1, 2017, 2:03 am Reply

thank you so much, this was so much help!


Mar 3, 2017, 5:48 am Reply

I realize the rules botanical painters work with are different, than e.g. painting landscapes, but the obvious question is why not use a larger flat or Hake brush for the wash?

Thanks for posting the video.


Jun 6, 2017, 7:47 am Reply

what masking fluid do you use?

Renee Marks

Jul 7, 2017, 8:28 pm Reply

I find it easier to wet my paper 1st beyond the demarcation line and allow it to settle in a few minutes and then start dropping in paint. Its fun and interesting to see the different methods that work great. Thanks for sharing.


Oct 10, 2017, 1:43 pm Reply

I'm definitely going to try this. Thank you for sharing!


Oct 10, 2017, 4:52 pm Reply

beautiful…..thank you

Judy Mason

Nov 11, 2017, 11:53 pm Reply

This was incredibly helpful, thank you!

Ido Perry

Dec 12, 2017, 3:12 pm Reply

Thanks! It's always challenging for me to create smooth background, I hope this vid will help 🙂

Renee L. Marks

Dec 12, 2017, 9:48 pm Reply

I use hot pressed with back ground washes all the time and they are always smooth. Susan Harrison-Tustain uses exclusively hot pressed Arches for all her watercolor paintings and she always has soft smooth beautiful backgrounds. You work wet into wet with back grounds and you must always wet way beyond your demarcation .

Debra Kellner Sawyer

Feb 2, 2019, 8:14 pm Reply

Thank you for sharing your valuable information, I will utilize it properly. I wish that I could afford to take your classes!

Mari Carmen Jiménez

Feb 2, 2019, 9:29 pm Reply

he comprado tu libro The Modern Flower painter, en inglés, me cuesta mucho traducirlo, me pregunto, si me animo a comprar alguna de tus clases, hay posibilidad de conseguirla en español?

Adji Pahlevi

Mar 3, 2019, 1:32 pm Reply

Thank you!!

Frances Turano

Sep 9, 2019, 9:44 pm Reply

This may sound like a silly question, but why not just go to the darkest application for the sky at the outset? Why 4 layers? This is very curious to me. Thank you.

Linda Martin

Sep 9, 2019, 1:55 am Reply

I wonder why you did not use a flat brush, work horizontally and at an angle, grasping the bead at the lower edge of the stroke to continue the next stroke? IF the color you use is consistently the same color and value, you might not even have to do four layers. Just curious. Your final product is lovely, just seems a bit like more work, but I am going to try it out!

Kim Daniel

Oct 10, 2019, 3:49 pm Reply

Over four years after this tip video was posted it remains invaluable. Being new to watercolor for just a couple months I’d not heard or seen on artist mention doing washes in layers not working on one edge at a time instead of doing the two as demoed in the first layer. One of the best watercolor instructors I’ve found on YouTube and am excited to try out the classes online.

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