# Halftone emulsion?



## speshoot (Apr 23, 2016)

is there a certain type of emulsion for printing Halftones, or it doesnt matter? right now im using Murakami Photocure Blu.


----------



## Twisted Grafix (Oct 5, 2016)

You can use any emulsion for halftones. It really comes down to a combination of the frequency, films, and exposure times. We use photopolymer daily, but have been successful with diazo too.


----------



## TABOB (Feb 13, 2018)

emulsion makes no much difference....Mesh count does.
The smaller the dots, the higher the mesh count required.


----------



## sben763 (May 17, 2009)

TABOB said:


> emulsion makes no much difference....Mesh count does.
> The smaller the dots, the higher the mesh count required.


This is definitely not correct. Diazo is a better choice especially for a novice. The latitude of exposure is much longer then photopolymer making the room for error greater. I personally is photopolymer (Saati PHU) with great results but I have everything dialed in. 

Not to mention different emulsions have different amount of solids, viscosities, and resistance properties. So all emulsions are not created equally and can make a world of difference. 

Also one can use a lower mesh for halftones by using a thicker coat of emulsion. This doesn’t work well when there is just a couple of dot like 99%-80% because there still needs to be a thread for the dot to hang onto. I’ve exposed 45 LPI on 128 mesh and 85 LPI on 272 mesh.


----------



## TABOB (Feb 13, 2018)

I don't agree.
I prefer keeping things simple and avoid problems caused by complexity. Time is money.


Personally, I rarely use emulsion, and when I do, I make my own using a spindle mixer. Surely any emulsion you buy from the shop must be better quality, but I never had a problems.


I use the same emulsion for everything, but I vary the mesh count.


----------



## speshoot (Apr 23, 2016)

TABOB said:


> I rarely use emulsion


???..how u screenprint, especially Halftones?


----------



## sben763 (May 17, 2009)

TABOB said:


> I don't agree.
> I prefer keeping things simple and avoid problems caused by complexity. Time is money.
> 
> 
> ...


You evidently don’t print much. You state emulsion doesn’t make a difference when it can make all the difference First off there are 2 types of emulsion, diazo(dual cure) and photopolymer. Diazo has a longer latitude which makes room for error and in most cases is stronger, more water resistant as well as not affected by humidity. Has a short shelf life 1-3 months, with cool storage I personally don’t recommend the fridge if your getting it out a lot as condensation can form. If one does they can pour off. I’ve had it last up to 9 months though just keeping in shop and heat @ 50 and AC @ 70. Then there is different solid contents as well as viscosity differences. A low solid low viscosity will make a thin stencil compared to a high solid high viscosity emulsion as well as how much of a build up you can obtain. 

Which emulsion are you making? I’m guessing the photopolymer recipe that’s on the net and if so you are not adding the buffers(sulfectants) so you are hammering your sewage facility with toxins, or if your on a septic or washing out in the outside those will end up in the ground water in 10-15 years. 

I never said use different emulsions. I use photopolymer for all but if someone just starting out or does enough to use dual cure they might want to go that route. A lot of auto shops run dual cure because it will outlast photopolymer. I’ve done 2000+ orders on auto with photopolymer with no problems but some shops run 10,000’s on a single run


----------



## sben763 (May 17, 2009)

speshoot said:


> ???..how u screenprint, especially Halftones?


I’m guessing cap film which is emulsion that already been dried. I remember this person in another thread saying vinyl sticker won’t work but that also works but for simple design small runs. Might also DTG


----------



## TABOB (Feb 13, 2018)

You make baseless assumptions...


No, I don't use toxic stuff. I don't want to get cancer. 

I use wallpaper glue (powder) and a powder sensitizer. I cannot remember the powder names, but I was given two options, and both were non toxic. I was told there is another very toxic option, which they could not give me without documentation. I was told they all work in a similar way (oxygen reaction when exposed to light) and they can be used to photo-sensitize many types of emulsions, including wall paint.



No, I don't use cap film either. I use a laser printer and thermoplastic powder. I cannot reclaim the mesh with this method, but I don't need to. There is no emulsion that can match the strength of this method, and water does not affect it at all.


----------



## sben763 (May 17, 2009)

TABOB said:


> You make baseless assumptions...
> 
> 
> No, I don't use toxic stuff. I don't want to get cancer.
> ...


Wallpaper paste -- often contains toxic preservatives, such as pentachlorophenol, arsenic, or mercury derivatives. Not to mention that when you add diazo or any other sensitizers I know of and the cross linking during exposure takes place now makes other compounds that are toxic. Baseless assumptions I think not.


----------



## OSSKOBRET (Sep 17, 2011)

Get some saati phu it is great stuff I use it for every type of ink I have
To the original OP.
Pay attention to Sean's words of wisdom I do not know of another person that has shared all his testing results to help others .
Look up his posts and do some reading You can gain a wealth of knowlege


----------



## TABOB (Feb 13, 2018)

Obviously you think I'm some idiot who doesn't have a clue...


The wallpaper glue I use is 100% plant cellulose. No fungicides no nothing. Why would I buy something clearly stating in the packaging that it contains fungicides, especially when I have no intention to actually use it for wallpaper? 

I was told PVA would be a better option, but I found it impossible to get 100% pure PVA, whereas 100% cellulose was easy and cheap. I think I paid around $10 for 1Kg which is enough to make 30-40 liters of emulsion.

Cross linking does not produce any toxic compounds. It just makes the exposed film water resistant.


Now remember, I was the first to admit that this is not the best emulsion you can have. But it does the job I want it to do perfectly, and so I assume any emulsion you buy from the store it has to be better.


For me varying the mesh with this homemade emulsion works just fine, but then I do mostly one color prints, and occasionally CMYK halftones. Also, I don't need to keep the exposed screens for more than 2 weeks,or print more than 300 shirts with it. So I'm not sure how my homemade emulsion would perform for something more demanding.


----------



## sben763 (May 17, 2009)

TABOB said:


> Obviously you think I'm some idiot who doesn't have a clue...
> 
> 
> The wallpaper glue I use is 100% plant cellulose. No fungicides no nothing. Why would I buy something clearly stating in the packaging that it contains fungicides, especially when I have no intention to actually use it for wallpaper?
> ...


The plant cellulose wallpaper glue (wheat dirivitive) contains preservatives. It simply would decompose otherwise when applied to the wall. I never said you were a idiot but are definitely uninformed. 


Crosslinking is the process of chemically joining two or more molecules by a covalent bond. Modification involves attaching or cleaving chemical groups to alter the solubility or other properties of the original molecule. 

This alters the original chemical structure. Just like water. H2O. Add a 2nd oxygen molecule and now you have hydrogen peroxide. Still going to drink it?


----------



## TABOB (Feb 13, 2018)

No preservatives. It is 100% cellulose, in 25gr sealed packs, and if I don't use distilled water, it will smell like a rotten potato after 2-3 weeks of mixing.



Adding an oxygen in H2O to make H2O2 is not cross-linking, as you are making a different molecule.


Anyway, I assure you, there is nothing toxic in my emulsion. I know what I'm doing.

​


----------



## sben763 (May 17, 2009)

TABOB said:


> No preservatives. It is 100% cellulose, in 25gr sealed packs, and if I don't use distilled water, it will smell like a rotten potato after 2-3 weeks of mixing.
> 
> 
> 
> ...



I can assure you you don’t. You said you were using wall paper paste power. They don’t make without preservative or it simply won’t last. I under stated adding a molecule to water is not cross linking. It was and example where 2 harmless things can be mixed to make something that can be very harmful. 

I wouldn’t take advice from someone that clearly doesn’t use products but yet tries to give advice. Just look at the current posts by this guy. 99% nothing but useless comments.


----------



## TABOB (Feb 13, 2018)

Well the package says 100% cellulose... but you must know better.


In any case I've not advised anyone to use my homemade emulsion. All I said is that in my experience mesh count is the most important thing when printing plastisol half tones. Obviously I use the worst emulsion possible, so surely any commercially available one will also work. 

I'm not talking about durability, or water resistance, solids content...none of that. What will happen after the 300 prints which is the maximum I do? This I don't know.


----------

