Making fake blood isn't exactly rocket science, but it's not child's play either. (Well, at least when you start going beyond ketchup and corn syrup.) I know that most everyone who has ever mixed up a batch of the red stuff are quite proud of their concoctions, but there is a lot more to think about than just how realistic it looks.
In the aforementioned conversation I had someone was telling me that they made blood using laundry stain remover as a base so that it would clean up easily. Not a bad idea...if you are planning on soaking laundry with fake blood. I asked what they did when it had to go inside an actor's mouth and was truly concerned when the response was that it “just tastes bad”. That told me that this particular person was using one formula as an all-purpose blood and wasn't thinking about the safety of the actors.
Why did this disturb me? Please allow me to explain. Laundry stain remover is a powerful detergent designed to break up organic matter. Yes, most household stains are organic in nature. And by the way, so is human flesh. In fact, one needs to look no further than the warning label on such products to know that it can cause skin irritation. (And that label is assuming that you might just accidentally get some on your hands while using the product for its intended purpose instead of deliberately dousing people with it.)
My speciality is blood effects, so this is a subject I'm pretty damned familiar with. I hardly ever just use one blood formula on a job. On the average, I use at least three and sometimes as many as eight different concoctions on a set. I've spent countless hours in my studio like some sort of maniac scientist experimenting with different blood brews to give me the effect I want on various surfaces. Some formulas bead up on glass while others don't. Some evaporate quickly while others gel up and look fresh all day. Some you could drink like shots of whiskey and others might kill you if you did.
And some require protective gloves while handling. I wouldn't dream of putting those on an actor.
There are a lot of things to think about when using fake blood. The most important for me is the safety of the people who will be in direct contact with it. When I'm selecting a formula to go onto an actor, I have to consider things like sensitive skin, toxicity, allergies, how easy it is to clean up, and the environment.
Yes, I said the environment. Gelatin-based blood won't solidify if the air temperature is too hot. Water-based bloods might freeze if the weather is too cold. And I refuse to use any blood that has a sugar or syrup base on an actor's body simply because it's a beacon for insects. In fact, I often mix insect repellent in my blood formulas if it's being used outside and especially in wooded areas. I call sugar/syrup-based blood “spitting blood” and the only time I ever use it is if it needs to go around or in an actor's mouth.
Need blood that will wash out quickly? Use a soap base. Need it to interact with water? Use vegetable glycerin base. Need blood that will stay put for long periods of time? Use a gelatin base. You get the idea. Nice, non-toxic bases that are often found in grooming products.
When making blood for skin applications, read the warning labels! Detergents can irritate or even burn skin. Soaps are very skin-friendly and work just as well for easy clean up. (Yes, detergent and soap are indeed two different things.) If something sounds like it would make a great blood base, check the ingredients first. Still aren't sure? Consult someone who knows more about chemistry than you do. And test your concoctions on yourself! Not just dab a bit on your hand for less than a minute to see if it looks good, paint your upper arm with the stuff and leave it on for a couple hours.
If at all possible, find out if the actors to be bloodied have any skin or food allergies. Some people have strange reactions to all kinds of things, so it's best to know this ahead of time. You don't want to mix up a beautiful batch of chunky, bloody vomit only to find out that the actor is highly allergic to the strawberry jam that went into it.
The second thing to consider (although many location-owners will insist that it should be the top priority)is how easy it is to clean up your bloody mess. This is important not only for staying in the good graces of the location manager, but also because it's quite likely you'll have to do a second take and you don't want the camera crew waiting around for hours while you're trying to make everything spotless again.
Consider everything on the set. What kind of floor covering is there? Carpeting is obviously going to be a far bigger concern than a hard floor is. Are there any soft furnishings (decorative fabrics like curtains) or upholstered furniture in the area that need to be protected? What's on the walls? You could have some big problems if they are papered or have paintings on them. Is the ceiling smooth or textured?
Cover everything that's not in camera frame with either drop cloths or plastic sheeting before you set off a blood splatter effect. If you have a stationary victim who is bleeding out, make sure the blood you use can be easily removed from the surfaces around them. And if you know that there is only one cleaning product in the world that will wipe up your blood, you'd better have a gallon of it onhand!
Which brings me to the subject of dyes. Very much like your base, you should match the type of dye you use with the application. If you need to dress a prop with permanent blood stains, by all means use fabric dye or ink to make your blood the proper shade of red. But don't use that same dye in blood that's going on an actor's costume or skin! Use cosmetic pigments. Food coloring seems to be the universal stand-by, but you do have to be careful with how much you use before it becomes a staining problem. And not all food colors are the same... the dye used to make cake icing red is much more housewife-friendly than the stuff used for coloring maraschino cherries.
Accidents and unexpected chemical reactions will happen, and it's important to make a note of them so you don't repeat the performance. I found out that one of my best“splatter bloods” is extremely difficult to wash out if it comes into contact with bleached hair. Guess what I now ask every blonde actor that needs head trauma?
If you don't want to bother with mixing your own blood and prefer to buy it ready-made, please don't think that you are out of the woods. Run stain tests with commercially-available formulas on as many different surfaces as you can and make a note of any difficulties. Figure out what cleaning products you need to remove any stubborn blood stains without harming the fabric, wood, skin, etc...
When running a stain test, you want to cover all of the common surfaces you are likely to encounter. Go to a home improvement store and get:
A carpet remnant (in a white or light color)
A tile of porous material (like stone)
A non-porous tile (like glazed ceramic)
A piece of untreated wood (pine is good)
A piece of finished wood (stained and sealed pine is good)
A piece of laminate
A vinyl tile
A piece of light-colored natural fabric (like 100% cotton)
A piece of light-colored synthetic fabric (like nylon)
A piece of white terrycloth towel (cotton-synthetic blend)
You'll also want to get a piece of drywall and leave one section plain, paint another section with satin wall paint, another with semi-gloss paint, paper another section with wallpaper and another section with textured wallpaper (or even better, fabric or flocked wallpaper.)
Test your blood formula on each one of these for staining and practice removing stains from any that prove to be tough to clean up. (If you're testing a blood to be put on actors, do a hair and skin test too!)
Yeah, I know... big pain in the ass. However, you'll find that it's time well-spent rather than getting screamed at (or worse) by a director, actor, or location-owner on a set.
Finally, please understand that nothing is 100% fool-proof when it comes to fake blood, so use your best judgement when asked to sling the stuff around. Inform everyone of any staining or reaction risks before you do the application. If you're using a soap-based formula, let actors know that if it gets in their eyes that they will probably be irritated for a short time but it is not very likely to hurt them. Make sure everyone knows not to try to taste any toxic concoctions. (Amazing how many people believe that all bloods are made with corn syrup.) And make sure you have a well-armed cleanup crew ready to spring into action when working with splatter effects.