Diazo-mixed emulsions are also cheaper and less of a headache for those just getting into screen printing. Say you expose a screen for 10 minutes, you could go over or under by a minute.ĭiazo emulsion works great with units that do not have timers and it can be washed out under UV light successfully (most of the time) without any issue, allowing you to wash out this emulsion outside. Since it takes longer to expose diazo emulsions, your window of error is larger. The diazo-mixed emulsion takes longer to expose but is more forgiving. The 10% window of error also applies to diazo-mixed emulsions. If the shop is in the mid-80s, the emulsion could last 2-5 weeks.
If you store the diazo emulsion on a shelf in your shop that's in the mid-70s, it could last for six weeks. Once mixed, the emulsion may last for two months if you store it in the fridge. Do not store it in an environment that's too cold because the emulsion can freeze. You don't want to use tap water because the minerals within the water make interfere with the diazo. When you mix the diazo, make sure to use water with a neutral pH balance like distilled water. This must be mixed into the the entire base prior to opening and printing for the first time, and is often referred to as “sensitizing” the emulsion. Photo by Golden Press Studio DIAZO (MIXED)ĭiazo (mixed) emulsion requires the addition of a Diazo powder before printing. More expensive compared to diazo-mixed emulsions.Ī good example of presensitized emulsion is Baselayr Complete.If slightly over or under exposed, you will have washout issues (remember the 10% window of error).Very sensitive - not for units without timers and needs to be washed out in light safe area.This kind is great to work into, but you may run into more issues if you get into this type too soon. For this kind of emulsion, you will want an exposure unit with a timer and a darkroom equipped with washout booth and supplies. If you are are a beginner, I would hold off on using this type of emulsion for a while. If the screen is over-exposed, you won't be able to wash out some of the finer details of the stencil. The 10% window of error would mean you could go six seconds over or six seconds under before you'd start seeing issues with your exposed emulsion. If the screen is under-exposed, parts of the image will wash out. For example, say you expose a screen for 60 seconds. When exposing a screen, you have a 10% window of error. If you wash the screens out outside, the emulsion would overexpose even the stencil. In fact, it is so sensitive that daylight on a cloudy day would start to expose your image. The downside of this kind is that it is VERY sensitive. This kind of emulsion is highly sensitive, exposes quicker, has a longer self-life and, captures fine detail beautifully.
There are two main categories of emulsion: Presensitized or Diazo (mixed). Once you have these answers, you can look at the pros and cons of each kind of emulsion and compare them to your resources and experience. What environment will I be washing out my emulsion in? Is it light-safeĪsking yourself these kinds of questions will help you save time and money in the long run.
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