A bloody buisness... (not for the faint of stomach)

Every time there is a show with blood it seems there is a need to re-invent the wheel.

The problem with there not being an obvious method is that every show has a different need for effect and application of blood.  
For one show the blood is supposed to come "gushing" from a wound, or the floor, or come dripping down from the skull... For another it may be a bloody nose (that is supposed to just coagulate and not run alot) The best and only kind I use for scabs and bloody noses is Ben Nye's fresh Scab.

There are different colors and viscosities.  
As far as viscosities go there are bloods formulated to be pumped through tubing called, oddly enough,  "pumping blood".

The pumping blood is most usually needed for "blood razors" in shows like Sweeney Todd.  Here is a video a prop master made to display his version of a blood razor;

Towards the end of the video you will notice that he tilts his hand away and you see that his thumb is on the expired blood pack attached to the razor (quite a handsome design I might add)

Colors;

Varieties of colors are typically "dark" and "light" with a wide variation therein between brands.  Mostly the color is chosen by where the wound is and how fresh it is ("arterial blood" is un-oxegenized and is darker whereas "venous blood" is generally brighter).  Often the lights will also factor in as to how bright blood should be (if there's a lot of blue light, the red of the blood becomes florescent and darker liquid is needed).  

A little tip though; blood can be made darker with a little green food color and brighter with a little glycerine or shampoo.

 Some blood is formulated to be safe to have in your mouth (not ingested) called "mouth blood". There is "film blood" that isn't uncommon on stage but what makes it special is that the color is especially realistic, and there is also just run of the mill "stage blood" that is usually too thick to go through tubing at a rapid rate but still a somewhat realistic viscosity to look like a wound. Usually your run of the mill "stage blood" is best in blood packs for war wounds and hand held head wounds. 

Drying is also a factor to consider.  When cleaning up blood, you want it to be wet, but if an actor is "bleeding" all over the stage it makes everyone's life hard.  

Many people will swear by some special blood formula that they've created but really unless you're in need of a lot of blood for a show (where the cost becomes prohibitive) I find that the commercially available stage bloods are best.  Mostly because of all of the engineering that has already gone into the commercial bloods they actually do what they are advertised to do and I find that they are more consistent and don't cause staining as much as the home made variety.

Re-inventing the wheel often means experimenting with new varieties of blood in order to insure that you get the correct drip time and color for your specific scene.  It also involves testing to see which kinds will stain skin;

and fabric.... you will note that I've tested three different types of fabric as well (Poly, silk and cotton)

Whenever you see blood on stage there has usually been  a great deal of experimentation with types and production meetings involving phrases like;

"when you gouge an eye, how much blood does it actually contain?  Would it just be clear?"

  "we'll let's pretend they went all the way through into the brain"

"ok, then how oxygenated is brain blood anyway?"

P.s. Please remember stage blood has a shelf life and usually isn't much good after about 6 to 10 months.  Have Fun!