The raw gesture
Gumoil allows applying oil pigments onto a photosensitized gum layer. Exposed areas harden and retain pigment, while unexposed areas remain soluble. The result is an image of incomparable organic quality.
Materials
Gelatin-coated watercolour paper 640 gsm · VP N°03 sensitizer · Oil pigments · Gum arabic
100% non-toxic
All our chemistry is reformulated by Vision Picturale to be safe for home use. No toxic products whatsoever.
In 4 steps
Make a Gumoil in 4 steps
Prepare
Sensitize the gelatin paper with VP N°03 mixed with gum arabic.
Calibrate
Print your negative on transparent film with the gumoil ICC profiles.
Expose
Expose with the Luminograph, then wash away unhardened areas.
Reveal
Apply oil pigments with a pad or roller onto the hardened gum.
Gumoil vs Bromoil
Gumoil or Bromoil: which process to choose for your intent
Gumoil and Bromoil are often confused because they share the idea of applying ink or oily pigment onto a photosensitive matrix. But their matrix, their gesture and their rendering are radically different — and the choice depends on what you want to express.
Bromoil starts from a thick, smooth gelatin. The pigment is Charbonnel intaglio ink, very fluid, applied with a foam roller. The rendering is soft, continuous, close to lithography. Ideal for portraits, still life, images demanding subtle tonal modulation.
Gumoil starts from a matte, slightly granular gum arabic. The pigments are thick oils applied with a pad or hard roller. The rendering is textured, raw, almost pictorial — much closer to engraving or oil painting than to photography. Ideal for landscapes, architecture, images that want to embrace their materiality.
In a sentence: Bromoil seeks grace, Gumoil seeks gesture. If you come from traditional photography and want to extend it toward the pictorial, start with Bromoil. If you come from drawing, engraving or painting and want to integrate the photographic image, start with Gumoil. Many artists end up practicing both.
Frequently asked questions
Everything about this process
What is the origin of Gumoil?
Gumoil is a pigment process developed in the 1990s by American photographer Karl Koenig, who published its detailed formulation in his book Gumoil Photographic Printing released in 1994. Gumoil combines the logic of pictorialist gum bichromate with oil inking: ground oil pigments are incorporated directly INTO VP N°04 gum arabic before exposure, unlike Aquaprint where powder pigment is dispersed then cleared in warm water. Gumoil Vision Picturale removes the dichromate from Koenig's historic formulations by using VP N°03 Universal Sensitizer on VP N°04 gum, mixed with ground oil pigments. The rendering sits between engraving and photography, with raw pigment carrying the image without intermediate dye.
Is Gumoil non-toxic in the VP version?
Gumoil Vision Picturale is non-toxic and free of aggressive petroleum solvent, unlike Karl Koenig's historic formulations which used white spirit. VP chemistry relies on VP N°04 gum arabic, VP N°03 Universal Sensitizer without dichromate, and ground oil pigments bound with food-grade linseed oil, without lead or cobalt siccatives. Brush cleaning uses vegetable oil then black soap, without any volatile product. The practitioner can concretely work on a kitchen table while ventilating the room, without an organic cartridge mask. Nitrile gloves remain recommended for handling oil pigments, which stain skin durably. Oiled rags must be stored in a closed metal container against any risk of self-ignition.
What are the steps of a Gumoil print?
A Gumoil Vision Picturale print follows a five-step sequence without aqueous clearing. The practitioner prepares a mixture of VP N°04 gum sensitized with VP N°03 Sensitizer, into which oil pigments are ground at the desired dosage, generally fifteen to twenty-five percent by mass. The layer is applied with a flat brush onto 640 gsm 100% cotton watercolor paper and dried for thirty minutes in darkness. Exposure under a 365 nm Luminograph A4 unit lasts two to five minutes depending on negative density. Reveal occurs through selective adhesion: a soft pad removes pigment from unexposed zones while UV-hardened pigment remains fixed on exposed zones. No clearing in warm water at 40°C, unlike Aquaprint. Final drying takes twenty-four hours.
How does Gumoil differ from Aquaprint?
Gumoil and Aquaprint Vision Picturale share VP N°04 gum and VP N°03 Universal Sensitizer, but differ radically in pigment and reveal. Aquaprint uses mineral powder pigments dispersed in aqueous gum, revealed by clearing in warm water at 40°C which dissolves unexposed gum. Gumoil incorporates ground oil pigments into the same VP N°04 gum, revealed without water by selective adhesion with pad or foam roller. Aquaprint allows CMYK four-color printing in four successive layers; Gumoil remains practically limited to monochrome or bichromic work. The practitioner will choose Gumoil for contrasted graphic images with matter-rich rendering, and Aquaprint for nuanced and faithful color images.
What skill level does Gumoil require?
Gumoil Vision Picturale is an advanced-level process, recommended after solid mastery of monochrome and four-color Aquaprint. The difficulty lies in dosing oil pigment within VP N°04 gum sensitized with VP N°03, which must stay between fifteen and twenty-five percent by mass: too little, the image lacks density; too much, adhesion reveal becomes impossible. Controlling pressure and speed of the pad or roller during reveal demands manual practice comparable to printmaking. In addition to the kit (VP N°04 gum + VP N°03), the practitioner must acquire extra-fine artist oil pigments from brands such as Sennelier or Old Holland, a frosted glass grinding plate, a grinding knife, and a high-density foam pad.
How permanent is a Gumoil print?
A Gumoil Vision Picturale print presents a stability estimated at several centuries, conditioned by the quality of the oil pigments selected. Oil pigments ground in polymerized linseed oil binder form, after complete drying of several weeks, an insoluble and chemically inert film, comparable to classic oil paintings whose multi-century stability is documented in the Louvre and Rijksmuseum collections. VP N°04 gum arabic hardened by VP N°03 Sensitizer is as stable as historic gum bichromates. The practitioner must imperatively use pigments rated ASTM I, avoiding organic lakes. Complete final drying takes three to four weeks at room temperature, during which the print must not be stacked or framed under glass.
An alternative
Want a Gumoil, not make it yourself?
Gumoil is a process of pad and pressure: each print carries the trace of the hand that made it. The printers of Maison Picturale make this their signature. Prints made in Paris, on 640 gsm gelatin-coated cotton paper, natural oil pigments.
Order a Gumoil
Maison Picturale · Paris 20e
