Surface and decoration · Wipe-away texture
Colour goes everywhere. The sponge decides what stays.
Flood a textured pot with a thin wash, let it go matte, then wipe the high points clean. The colour that stays in the recesses turns a texture you could barely see into the whole design.
This page walks it in the order the pot wants it, with a tick list at every step, the underglaze and oxide versions side by side, the glazes that show it and the glazes that bury it, six fixes and five videos.
This is the short version: the mix, the wait, the wipe, and the glaze rule. The oxide details, the reasoning and the questions are in the comprehensive version.
Read it, then watch it
Why this is written down and filmed, both.
The wipe is a feel. How damp the sponge is, how hard you press, when to stop: none of that survives a sentence, and a wipe-back done with a sponge that is a little too wet is a plain pot. So the videos are here for the sponge. The mixing ratios, the order of operations, and which glazes will hide your work are the other half, and that half is what people forget between the bench and the glaze wall, which is why it is written down with a tick list under it.
Use both, in this order
Read the step. Watch the sponge. Do it with the tick list open. The page remembers your ticks, so you can wash a pot on Tuesday and glaze it on Thursday without losing your place.
The whole idea
Colour goes everywhere. The sponge takes it off the top.
Paint a thin wash over a textured bisque pot, let it go matte, then wipe the high points clean with a sponge wrung nearly dry. What stays in the recesses is the design. A see-through glaze goes over the top and the texture reads from across the room.
The five-minute version
The whole technique in six moves.
If you already glaze and you just want the shape of it, this is the shape of it. Everything below is these six moves, slowed down and with the places they fail marked.
Six moves. The tick lists below are these six broken into things you can do with a sponge in one hand.
Before you open a bottle
What you need on the table.
Six things. The sponge is the one that matters, and the glaze is the one people get wrong.
A textured bisque pot, a bottle of underglaze in a strong colour, a small pot of water, a wide soft brush, a clean sponge with a bucket to rinse it in, and a glaze you can see through. That is all of it.
Step one
Texture first, bisque second, and only then the wash.
The texture is the design. The wash only reveals what is already there, so the evening is decided at leather hard, long before any colour comes out. Stamp it, roll it, carve it, add sprigs, or build from a textured slab. Anything with real recesses works. Anything smooth does not.
Then bisque it. This is the step people skip because they are impatient and it is the step that ruins the pot. A wet sponge on greenware dissolves the surface, pulls clay off the high points along with the colour, and leaves a smeared mess that dries into a smeared mess. Bone dry greenware is worse, not better, because it drinks the wash and will not give it back. Bisque is the answer: porous enough to take colour, hard enough to be wiped fifty times without complaint. Our bisque firing is cone 05 and it is free.
Before the wash, wipe the bisque with a clean damp sponge and let it dry for a minute. This lifts kiln dust and fingerprints, both of which are why glazes crawl later, and it gives the surface an even thirst so the wash goes on evenly. Handle the pot by the foot from here on. Skin oil on the surface is a crawl waiting to happen.
How deep is deep enough
Deeper than the sponge can reach, which is only about a millimetre. A firm stamp press, a roller with real relief, or a carved line all qualify. A light fabric impression is borderline: it will take a wash, but you will need a stronger mix and a lighter hand, and the result reads as a tint rather than a pattern. When in doubt, press harder at leather hard. You cannot add depth at bisque.
Step two
Mix a thin wash and flood the whole surface.
One part underglaze, two parts water. That is the starting mix. It should look like weak tea, and it should look far too thin. It is not. Bisque drinks the water and keeps the colour, and a wash that looks right in the pot is a wash that will not wipe off.
Stir it every time you load the brush, because pigment sinks. Then paint it on everywhere with a wide soft brush, working it into the recesses, going round the pot twice if the first pass looked patchy. Do not be neat. Neat is what the sponge does. A wash that is applied thinly and evenly wipes back thinly and evenly; a wash slapped on in one heavy coat gives you a dark half and a pale half.
Then wait. A few minutes on a warm evening. The surface goes from shiny to matte as the bisque pulls the water in, and matte is the signal. A shiny wash is a wet wash, and a wet wash moves sideways under a sponge instead of lifting off. If you are doing several pots, wash them all first and start wiping the first one; by the time you finish, the last one is ready.
Red iron oxide, and the rest
A teaspoon of red iron oxide in a small pot of water is the classic wash: cheap, warm, forgiving. A pinch of a clear glaze or a little frit in the mix helps it stay put on the pot instead of dusting off. Cobalt is far stronger, a quarter teaspoon is plenty; copper goes green and can run; manganese and chrome are the ones to be genuinely careful with. All of them are metal compounds. Mix them wet, wear a respirator if you are handling dry powder, keep them off your skin, and never eat or drink at the bench.
Predictable, and it stays where you put it
Underglaze is a finished colour with the flux already balanced. It comes out of the kiln the colour it went in, it does not run into the glaze above it, and a thin wash of it wipes back cleanly. Oxides interact with whatever glaze sits on top, which is either the whole point or the whole problem depending on the day. Learn the technique with underglaze, then play with iron once you know what a good wipe looks like.
Step three
Wipe the high points, and stop before you think you should.
The sponge is wrung out until it is barely damp. Wipe in one direction with a light hand. Rinse it, wring it, wipe again. The high points come clean and the recesses stay full. Stop the moment the surface reads the way you want, because every pass after that takes colour out of the texture too.
Three things go wrong here, and they are all about water. A sponge that is too wet floods the recesses and lifts the colour out of them. A sponge that is not rinsed between passes puts the pigment it just collected back down as a grey film. And a sponge dragged in every direction leaves crossed streaks that read as carelessness, where one direction reads as a decision. Rinse, wring, one direction, light. That is the whole skill.
How far you wipe is taste. Wipe hard and the high points go back to bare clay and the pattern is crisp and graphic. Wipe lightly and a tint stays on the surface and the whole pot goes a shade warmer, with the texture darker still. Both are correct. What is not correct is deciding halfway through, so look at the first pot and decide before you start the second. If a section goes wrong, wash it again: bisque will take a second wash and a second wipe without any trouble.
The rinse water
Underglaze rinse water can go down the sink in a studio with a clay trap, which ours has. Oxide rinse water should not go down any sink: let it settle in a bucket overnight, pour the clear water off, and wipe the sludge into the bin with a paper towel. Cobalt, copper and manganese in particular do not belong in the drain.
Step four
Glaze with something you can see through.
An opaque glaze erases the evening. The wash lives under the glaze, so the glaze has to be one that light gets through: a transparent, a celadon, a translucent satin, most honey and amber glazes. A white gloss, a heavy satin or three fat coats of anything opaque and the texture is gone for good.
Celadons and translucent glazes do something extra: they pool thicker in the recesses and thinner on the high points, which doubles the effect the wash started. A washed and celadoned texture reads from across a room. Our celadon lesson covers which ones pool and which ones do not. Keep to the maker’s coat count: a third coat that turns a translucent glaze milky is the most common way a good wipe-back disappears.
Transparent
Shows the wash exactly as you left it. The honest choice for a first pot, and the one that teaches you what your wipe actually looks like.
Celadon and translucent satin
Tints the whole pot and pools darker in the texture. Iron washes go olive and amber under green celadons, which is the classic look for a reason.
Nothing at all
A decorative piece can stay raw: underglaze fires to a dry matte skin, iron to a soft metallic one. Never on a food or drink surface.
Wash over glaze, the variation
Some potters brush an oxide wash over an unfired glaze coat instead of under it, and wipe or blend it there. It gives soft, mottled, painterly results and it is much harder to control, because the wash can flux the glaze and run. Richard McColl’s video below is the one to watch if you want to try it. Treat it as a test tile technique until you have seen a few fired.
Watch it done
Now watch five people do this five ways.
Watch this one, then go wash a pot.
None of these potters work here or know we exist. Between them they cover the underglaze version, the sponge itself, the iron oxide version, what it looks like fired, and the over-glaze variation. Nothing but the still frame loads until you press play.
Six minutes, the underglaze method on bisque with a celadon over the top. The other four videos are in the comprehensive version.
When it goes wrong
Six ways it goes wrong, and what to do about each.
The three failures that happen on the first night.
Pick the one that looks like your pot. The first three are sponge problems. The last three are glaze problems, and two of them are permanent.
The wash will not wipe off the high points
Too much pigment, or the pot was too thirsty. Underglaze at full strength soaks into bisque and stays. So does any wash left to dry for an hour before you came back to it, and so does a wash on greenware, where wiping just moves clay around.
Thin the underglaze, one part colour to two parts water at least, and wipe as soon as the shine has gone. Work on bisque, not greenware. A softer bisque, or a pot that was damp before the wash went on, releases more easily.
Use a slightly wetter sponge and more passes, rinsing every pass. A green scrubbing pad, used gently, will lift stubborn colour off flat high points. If the piece is dry and nothing moves, a light sponge with clean water first will soften the wash enough to work.
It came off the recesses too and the pot is plain again
The sponge was too wet, or the wash was too thin, or you kept wiping past the point where the high points were clean. The recesses only hold colour if there is enough of it and if the sponge cannot reach the bottom of them.
Wring the sponge until it is barely damp. Wipe in one direction, lightly, and stop the moment the high points read clean. Shallow texture holds less; if the pattern is faint, the wash needs to be stronger, not the wipe gentler.
Let it dry and wash it again. Bisque forgives this completely. Second time, thicker mix and a drier sponge.
Streaks and a muddy film over everything
A dirty sponge. Every pass loads the sponge with pigment and every unrinsed pass puts it back down somewhere else. Wiping while the wash is still wet does the same thing.
Rinse after every single pass, wring it out, and wipe in one direction so the drag pattern reads as intentional. Wait for the wash to go matte before the first pass.
Rinse the sponge properly and go over the high points again with clean water. If a faint film stays, a translucent glaze will make it look like a deliberate tint, which it now is.
The texture showed on the shelf and vanished in the kiln
The glaze on top was opaque, or thick enough to behave like it was. A wipe-back lives under a glaze you can see through. A white gloss, a heavy satin or three coats of anything opaque buries it.
Choose a transparent, a celadon, or a translucent satin, and keep it to the manufacturer’s coats. Test the pairing on a scrap tile first; the glaze wall is enormous and half of it is opaque.
Gone is gone. Fired glaze does not come off. Put the pot in the kitchen and put the lesson in the next one.
The glaze crawled away from the washed areas
Glaze needs to grip the surface, and a thick layer of underglaze or wash is a powdery layer it cannot grip. Dust from sanding, oil from hands, and a pot that was still damp when it was glazed do the same thing.
Thin wash, wiped back hard, and a full dry before glazing. Wipe the pot with a clean damp sponge before glazing to lift any dust. Handle bisque by the foot.
If it crawled in the bisque-to-glaze firing, a second glaze firing after refilling the bare patches sometimes heals it. Often it does not. Our glaze problems lesson covers the refire decision.
The colour bled into the glaze and ran
Too much oxide under a glaze with movement. Iron and cobalt are fluxes as well as colourants, and a heavy wash under a runny glaze turns into a runny, coloured glaze.
Thinner wash, wiped back properly, and a stable glaze over it. This is the reason we teach underglaze first: underglaze does not flux the glaze above it the way raw oxides do.
If it ran onto the shelf, it is a grinding job and possibly a fee. If it stayed on the pot, it is a pot with an interesting glaze. Our fused pottery lesson covers the grinder.
How it works here
At The Clay Hole, this is an underglaze technique.
This page is written for potters everywhere. A few things are specific to our building, so you know before you start.
Four things to know here
We teach the wash with underglaze from our wall of 150+, which needs the free brush-on glaze and underglaze certification first. We do not sell oxides or washes; check with the studio team before bringing in anything that goes into our kilns. Bisque is cone 05 and free; glaze firing is cone 5½ at five cents a cubic inch. The rinse sink has a clay trap; oxide water settles in a bucket instead.
Underglaze from the wall
The 150+ underglazes are the tool we teach this with, and they are open to anyone who has done the free brush-on glaze and underglaze certification. It takes about half an hour, once. Get certified here. Thin it in your own pot, not in the bottle.
Oxides
We do not sell oxides or commercial washes, and this page teaches them for potters who have their own. If you want to bring one in, talk to the studio team first, because anything that goes into our kilns needs to be something we know about. Our glaze firing is cone 5½, and iron behaves well there under most see-through glazes.
Texture worth washing
We have 150+ slab molds, many of them textured, and sprig molds, stamps and rollers in the building. The slab roller and slab mold certification opens the slab room. Our eight clays are all light or medium, which is the ideal ground: a dark wash on pale clay is the whole effect.
Firing and the sink
Bisque is cone 05 and free. The glaze firing is cone 5½ at five cents a cubic inch, $4.80 minimum. The rinse sink has a clay trap, so underglaze water can go down it. Oxide water cannot: settle it in a bucket and bin the sludge.
They are metals. Treat them like it.
Iron is the gentle one. Cobalt, copper, manganese and chrome are not. Mix them wet, wear a fitted respirator around any dry powder, keep them off your skin, and do not eat at the bench. Rinse water settles in a bucket, never the sink.
They are metals. Treat them like it.
Red iron oxide is the gentle one, and it is still a fine metal powder you should not breathe. Cobalt, copper, manganese and chrome are genuinely toxic in the quantities a careless potter can inhale over a year. The rules are short: buy them as powder and mix them wet, wear a fitted respirator with P100 cartridges around dry powder rather than a paper mask, keep them off broken skin, wash your hands before you eat, and settle the rinse water rather than pouring it away. An N95 is better than nothing and worse than a respirator. Underglaze carries none of this: the pigment is already bound in the bottle, which is one more reason it is the version we teach.
Questions people actually ask
The ones that come up every week.
Do I do this on greenware or bisque?
Bisque. Greenware dissolves under a wet sponge, the wipe pulls clay off the high points along with the colour, and underglaze on bone dry clay soaks in and will not release. Bisque is porous enough to take the wash and hard enough to let you wipe it as many times as you like.
What is the difference between an underglaze wash and an oxide wash?
An underglaze wash is bottled underglaze thinned with water. It is a finished, predictable colour that stays put in the kiln. An oxide wash is a raw metal oxide, usually red iron oxide, mixed with water. It is cheaper, more traditional, and it interacts with the glaze on top: iron goes amber under a clear, olive under a celadon, and can run under anything with movement. Underglaze is the one we teach here.
Can I use it under any glaze?
Under any glaze you can see through. Transparent, celadon, translucent satin, most of the amber and honey glazes. An opaque glaze hides it completely. Test the pairing on a tile before you put a pot you care about under it.
How thin should the wash be?
For underglaze, start at one part colour to two parts water and adjust. Too thin looks weak in the recesses; too thick will not wipe off the high points. For red iron oxide, a teaspoon in a small yogurt pot of water is a common starting point, and it should look like weak tea, not coffee.
Can I leave the wash unglazed?
On a decorative piece, yes. Underglaze fires to a dry matte surface and an oxide wash fires to a metallic or matte skin, and both can be lovely on a vase or a wall piece. On anything that touches food or drink, no: an unglazed wash is porous, it can be rough, and raw oxides should never be a food surface.
Does the texture need to be deep?
It needs to be deeper than your sponge can reach, which is not very deep. Stamped, rolled and carved textures all work. Very shallow texture, like a light fabric print, holds less colour and needs a stronger wash and a lighter wipe. Our imprinting textures lesson and sprig molds lesson cover making texture worth washing.
Why does everyone use red iron oxide?
Because it is cheap, forgiving, relatively low in toxicity as oxides go, and it gives the warm rust and amber tones that make texture look old. Cobalt, copper, manganese and chrome all work too and all of them are more toxic to handle, stronger per teaspoon, and more likely to run. Iron is the beginner oxide for good reasons.
Related lessons
Six lessons that sit next to this one.
Three to read next.
A wipe-back is only as good as the texture under it and the glaze over it. These are the lessons on either side.
That is the whole technique
Flood it, wait for matte, wipe it back, glaze clear.
Your first one will probably be wiped a little too hard or glazed a little too thick. Both are fixed on the second pot. Almost nothing in this building turns a plain textured pot into something people pick up as reliably as this does, and it costs a teaspoon of underglaze.
If you want the oxide version, the glaze pairings, and the answers to the questions everybody asks, switch to the comprehensive version at the top. Otherwise, go find a textured pot.
Written for potters everywhere. Where our studio does things differently, the page says so.
Which version would you like to print?
Both print clean, with the videos turned into labelled boxes you can search for later.