Aluminium Prints That Let the Metal Show Through: How the Look Is Made

Print a picture straight onto aluminium with no white ink underneath and the metal becomes the lightest tone of the image. UV colour inks are semi-transparent, so the aluminium shows through the printed tones as well as between them. The result reads as a photograph made of metal: it flashes and changes as you walk past or as the light moves.

Sun Studio prints this way directly onto the metal at its studio in Al Quoz, Dubai. This guide is about the look: why it happens, how much metal shows, which images suit it, how to approve it and where it is used. Sheet sizes, the metals we print on and what to send for a quote are on our page for metal and aluminium printing in Dubai.

What this piece shows

The piece in these photographs is a monochrome halftone photograph of classic saloon cars in front of a building. Sun Studio printed it on its Direct Color Systems UV44 flatbed, straight onto brushed aluminium sheet, with no white base under the ink and no clear coat over it, so the shine is the aluminium itself.

Three things are visible. The metal is the lightest tone of the picture, so the highlights are the aluminium. The metal also shows through the printed tones, so the darker areas carry a sheen too. And up close the picture breaks into halftone dots.

The right-hand part of the picture is printed lighter than the left. More metal shows there, so that side reads brighter.

Why the metal shows through the ink

Roland DG notes that because CMYK digital ink is semi-transparent, the surface it is printed on affects the final appearance, and that on shiny metal it can mute the colours. Its remedy is a high-opacity white printed underneath as a sub-coat.

That white base is the normal choice when a colour has to be right. Leave it out and the metal becomes part of every tone. Light passes through the ink, reflects off the aluminium and comes back through the ink to your eye, so the printed tones take on the metal's sheen and the lightest areas are the metal.

Aluminium reflects light, so what you see depends on where the light is and where you stand. As you move, the bright reflection slides across the picture and the tones seem to shift. Where white is printed underneath, the metal is hidden, so those areas do not change with the light.

Why you can see dots up close

A printer builds shades of grey from dots, not from a separate ink for each shade. A dark tone has more ink and smaller gaps. A light tone has smaller or fewer dots and wider gaps. Roland DG's explanation of screening describes both methods: dots that grow larger for darker tones, or dots of one size placed more densely.

On paper the gaps are white paper. On aluminium the gaps are metal, which is why the light parts of the picture shine the most. The dots are part of the look, not a fault.

In this piece the dots are plain to see up close, which gives the photograph a graphic, printed quality. With any halftone, the further back you stand, the more the dots merge into continuous tone. How visible the dots should be is a design decision to settle before printing, in the artwork or in the print settings.

Controlling how much metal shows

How much aluminium shows is set in the artwork, not left to chance. Three controls do the work.

• Tone and ink amount. Lighter tones lay less ink, so more metal shows. Roland DG, writing about metallic media, notes that varying the amount of ink printed directly onto a metallic surface changes the result.
• White only where something must read solid. A logo, lettering or a colour block can have white printed under it while the rest of the picture stays see-through. Printers call this spot white or a white mask. EFI's guide to white and clear printing describes the same idea: white masks off chosen areas, and metallic substrates show through the colour wherever white is absent.
• An optional clear varnish. A clear layer over the top changes the sheen and takes handling wear. Whether a piece needs one depends on where it will hang; this piece has none.

Where a solid element fades into the see-through part, the white under it has to fade with it. That is prepared in the artwork as its own layer.

Which images suit the look

The piece shown here is monochrome, which makes the effect easy to read: the dark tones carry the picture and the aluminium plays the highlights. Black and white photographs, duotones built from two ink colours, and images with strong contrast and real light areas all leave the metal room to show.

Full-colour photographs can be printed without white too, but the metal tints every colour. Pale tints almost disappear and whites become silver. An image that depends on bright white, such as snow or a white product, loses it, because on metal the brightest tone is the aluminium. If colour accuracy matters, put white under those areas or choose a white-backed print.

Think of the metal as the white of the picture when you prepare the file, and send the highest resolution you have, because a piece like this is looked at close up. Our guide to preparing artwork for UV printing covers file types and how to mark which elements must stay opaque.

Brushed aluminium or a white-backed print

This is a choice of look, not of quality. Printed over white, a picture on aluminium behaves like a photograph on a white ground: accurate colour, clean whites, and metal only where the design leaves it bare. Printed without white, the picture is made of metal: the highlights shine, the darker tones keep a sheen, and the whole piece changes with the light.

Either way the photograph is printed onto the metal, not mounted on it, as on the historical photographs and text we printed onto aluminium display panels for Sharjah Heritage Museum.

A brushed aluminium print adds fine lines running in one direction. Where the metal shows, those lines catch the light and give a soft, directional shine, and the grain reads under the thinner printed tones. Mill-finish, polished and anodised aluminium are different grounds again, so a sample on one finish does not predict another.

The finish also decides preparation and adhesion. Which surface takes ink well, and why a brand colour needs white under it, is covered in which metal finish takes UV ink best. Cleaning and pre-treatment are in why UV print peels.

The same decision appears on smaller pieces. Our badge and name plate guide shows white withheld so the metal becomes part of the design. On gold and silver the idea goes further, with the background printed and the metal left as the artwork: see precious metal printing in Dubai. Aluminium composite panels can be printed the same way: see ACP panels with a brushed or metallic face.

Approving the look before the full piece

Approve it on a sample printed on the actual metal, under the light it will hang in. A screen or a paper proof cannot show the effect, because neither has a metal ground and neither changes as you move.

• Supply the aluminium, or an offcut of the same sheet and finish.
• Sample a section of the picture that includes its darkest, lightest and middle tones.
• Look at it under the planned lighting, from the distance people will stand, and while walking past.
• If it reads too dark or too flat, lighten the tones, or add white where something must read solid, and sample again.
• Keep the approved sample. A different batch or finish of aluminium can change the ground under the ink, and the result with it.

Where the look is used in interiors

The look is used as metal wall art in interiors: reception and lobby artwork, feature walls and panels in hotels and restaurants, office corridors and meeting rooms, and brand pieces where metal suits the identity. Because the reflection changes with the light, the look suits places people walk past and spaces with directional light, such as spotlights or daylight from one side.

There is no minimum order, so a single art piece is a normal job.

How it differs from a sublimated metal photo panel

A similar look is sold as a ready-made metal photo panel. ChromaLuxe, one maker of such panels, offers its coated aluminium with a white base or a clear base, and on the clear base the brushed aluminium shows through; the image is sublimated, with heat driving the dye into that coating. Direct UV printing puts the ink straight onto the metal, with no sublimation coating or heat press, so white can go under some parts of the picture and not others. The wider comparison is in UV printing vs screen, pad and sublimation.

Aluminium print or acrylic print

A print on clear acrylic is seen on or through the sheet, which gives it depth and gloss. On clear sheet, white goes behind the colour wherever it must read opaque. An aluminium print without white does the opposite: the picture sits on the metal and the metal is part of it. Choose acrylic for colour and depth, and aluminium for a picture that shines and changes with the light. Our explainer on how acrylic printing works covers direct print, reverse print and face mounting, and the service is acrylic printing in Dubai.

Indoors, outdoors and humid rooms

Indoors, how long a print lasts depends on the surface and how it was prepared. What decides it, including the role of a varnish, is in how long UV printing lasts.

Outdoors, UAE sun fades colour over time, and heat and moisture test the bond to the metal. Tell us if a piece is going outside or near water: we test a sample rather than promise a life.

The see-through areas are metal, so the metal's own behaviour matters too. The Aluminium Federation notes that long exposure to moist air can leave a slight white to grey film on aluminium, easy to rub off. If the piece will hang in a humid space, say so in the brief.

Common questions

To ask for a quotation, send the image and where it will hang. Email info@sunstudio.ae or call +971 4 346 7422, and we will tell you what the sample should show.