printing on metal (brushed Aluminium prints)

[Roland Vink]

I skimmed this thread quickly so apologies if I missed anything. Basically you are printing black on brushed aluminium, so the image is not "black and white", it's "black and aluminium". That gives you the reduced range of tones, and printing any light detail in the cloud has to be in black ink, which covers the aluminium and results in a flat image.

Could you consider printing black and white on aluminium? Of course the image will be different, no brushed aluminium will show because any white parts will be white ink. Is that an option? That would at least give you a wider range of tones to play with...

[elsa hoffmann]

Roland - well explained.
The print is in question as the client is moaning over the costs and I am not budging on my price.

[elsa hoffmann]

I went down to my local dealer today, and stopped by the Lab while I was there. The Lab guys told me that they don't do printing on metal, beyond using metallic papers. So much for my effort to see an example. I was surprised that they din't do it, because this it is the local lab preferred by pros, but they said that it's not for everyone, as it doesn't always turn out the way people expect.

Carl  - thanks for taking the time to check. I believe it's a relatively new medium to print on - and believe me - nothing beats the right print on metal - it's in another class altogether. 

[Roland Vink]

OK, so no white ink.

You are currently aiming for a photo-realistic print. Given the limitations of the medium you might consider a more "graphical" rendering:

Maybe by posterizing the image (using only a small number of different tones)

Or by using halftone like black and white pictures in newspapers. I'm sure I have seen this used effectively on metal prints - light detail such as the wispy clouds would be rendered as very small discrete dots so you still get the aluminium showing through. Viewed from a distance the dots are too small to see so you still get a photo-realistic image.

Hope that helps.

[CS]

Roland - well explained.
The print is in question as the client is moaning over the costs and I am not budging on my price.

Here's a 20, or so, minute video on metal printing that I thought had a lot of good info. I knew that  I didn't know much about metal printing, but I didn't know how much I didn't know until I watched this video. The difference in quality from various printing sources was eye opening.

https://www.bayphoto.com/wall-displays/metalprints/

[elsa hoffmann]

from what I could see the guy was talking about printing on gloss or mat metal. (video bombed out 2.3 thru) And the stuff they show is colour. Mine is a B&W image. My print shop prints Di-bond  on brushed Aluminium. That makes a really really big difference - as the brushed effects gives texture. As you know - white falls away and shows the brushed Aluminium effect. I have looked at a couple of videos now - and not a single one is able to show the true effect on video. By it's nature it is not suitable for being filmed.

[CS]

from what I could see the guy was talking about printing on gloss or mat metal. (video bombed out 2.3 thru) And the stuff they show is colour. Mine is a B&W image. My print shop prints Di-bond  on brushed Aluminium. That makes a really really big difference - as the brushed effects gives texture. As you know - white falls away and shows the brushed Aluminium effect. I have looked at a couple of videos now - and not a single one is able to show the true effect on video. By it's nature it is not suitable for being filmed.

I know that video didn't address your particular B&W image process, but, it did show that there's a night and day difference in finished quality between aluminum print sources. it also mentioned that they have 5 different choices for the finish on the metal itself.

Anyway, I posted the link to that video to show more about metal printing in general than as remedy for your image efforts. Didn't mean to hijack the thread, it just seemed to me that it fit in.

[elsa hoffmann]

Carl - you didn't hijack the thread at all - and I am quite pleased you posted the link - as I then got on to other links as well. Hoping to find my process - only to see that I couldn't - well not that I could find anyway. It is disappointing that one cant' really see the final effect as I really would have liked you to see it. I was really impressed with the sample they had up on their wall in the print room. Wish I could share that - showign what I saw.

[simsurace]

Just to clarify:
There are many different products of prints on metal that you can buy.

- Direct printing on Alu Dibond
- Direct printing on brushed aluminium
- Mounting a paper print to aluminium
- Metalprint

The last seems to be a fairly new dye sublimation technique (I think it wasn't available when I ordered my print, but I may simply not remember). There is a coating on the aluminium. The photo is first printed on a transfer paper which is laid onto the coated aluminium (I think the coating is polyester). Then heat is applied. EDIT: after reading some more, it seems to be a fairly old technique actually, much older than inkjet printing.

Metalprint and direct printing on brushed aluminium do show the metal texture in the highlight areas. The others show white, either because of the paper or a white base layer.

On Whitewall there are some videos showing a glimpse of the process. Unfortunately, they are in German. But you can see some stuff.

Direct printing on alu: https://www.youtube.com/watch?v=A9aqc2l9nBk
Direct printing on brushed alu: https://www.youtube.com/watch?v=LFdgiWfUCVk
Paper on alu: https://www.youtube.com/watch?v=A9aqc2l9nBk
Metalprint: https://www.youtube.com/watch?v=XGMdbp73PWs

[CS]

Thanks, Simone, very helpful.

[David H. Hartman]

A caution regarding mounting a paper print directly on unfinished aluminum. I mounted two fiber base prints using a water based adhesive. All went well for a couple of decades in dry Southern California homes but finally the aluminum blistered a bit so there are little bumps distributed across the prints. The aluminum is 6061 T6 and untreated. It was really slick if only it had lasted. I squeegeed the wet print directly on the aluminum and let them dry in place.

Dave Hartman

[elsa hoffmann]

Thanks Simone.
Dave - I assume you wont have those reprinted then?

[elsa hoffmann]

Some more info on DiBond -
Half the weight of aluminium, Dibond® is a rigid, durable, aluminium-composite material consisting of two pre-painted sheets of 3 mm aluminium bonded to a solid plastic core. It is an excellent replacement for aluminium, MDF (medium-density fibreboard), plywood, thick gauge plastics and some laminated fluted/solid core sheets.

The above is one of the only methods to achieve a completely flat finish in framing.

[David H. Hartman]

Thanks Simone.
Dave - I assume you wont have those reprinted then?

I did the printing decades ago. l had a business shooting PR and I also printed other PR photographer's negatives. I did the color printing for one high school's year book as the pints had to be printed exact size for paste up. I printed the the color prints 3mm over size and the year book teacher cut them off with a drafting triangle and X-acto knife. I was a semi professional photographer as I made less shooting than printing. The business died when color web printing replaced B&W printing for charities and hospitals. I tried to buy a color scanner and move to supply digital page layout. At that time the work flow was to scan color negatives and do the layout in Page Maker or Venture Publisher.

I still have a full wet darkroom but it lacks sewer line as I had to cut the improvised one on the outside of the house. I'd like to shoot a little B&W in 35mm and 4x5 but I'll have to get brave and cut the concrete floor of my garage to do a proper job of installing a sewer line.

Anyway I've never reprinted those negatives.

Dave Hartman

[Alaun]

The “metal prints” (White Wall, Bayfoto) use a special feature of aluminium: Al is always covered with an Al-oxide layer.
 
They do not print onto the surface but into the surface. They use anodised aluminium plates and they bring the color into the anodised layer. Actually the anodising process is not finished, when they do the printing. The color is supplied via the print on paper (as in the above referenced video by CS) or they use ink jet printers to directly print on/into the surface.

Anodizing is a kind of electrolytic process, where you increase/grow the layer of Al-oxide, which is always on top of any aluminium surface. After the electrolytic part of the process, this Al-oxide layer (actually a Al-hydroxide-layer) is not yet very dense but a kind of porous. They print (or sublimate) the color into this oxide layer. Then there is a final step (kind of cooking in water) where this surface layer is densed/hardened, you get an almost corundum like Al-oxide layer with the picture inside. This layer is far more stable (time, UV, scratching) than any lacquer. E.g. this printing process is used to make signs, which are resistant against abuse in public areas.  This process is a kind of further development of what you might know as coloured anodized aluminium (or Eloxal).

I looked for a reference for the printing and prints, it seems the prints are called “sub-anodizing prints”. 

http://www.directcolorsystems.com/applications/anodized-aluminum-printing/
   
By the way, he Dibond plates use 0.3mm Al-sheets (not 3mm), which are made from rolled 5005 alloy (AlMg1) in H44 (heat treating condition).