Dean, assuming your steel is clean, no oil or residue, the straw color is lower and the blues and purples are hotter. Search the internet for temper heat color chart, thousands of images.

Thank you Steve, so do I assume I went pass the straw color maybe because my oven temp was too high or the steel stayed in too long? Or the opposite? Did I not leave it in long enough or the temp was too low to go past the blue and onto the wheat?

I'm sorry just a little confused on this issue.

Yes, blues and purples come after straw, but I have found that tempering colors can be a pretty unreliable indicator of temperature. Surface contaminants and possibly even atmospheric issues can cause unexpected colors to appear. I simply put an oven thermometer inside of my tempering oven to double check that my readings are accurate. But I should also add that some ovens will heat unevenly or create hot-spots, which can lead to inconsistent results. Perhaps taking care to keep the blade as far away from the heating elements as possible, simply by placing it right in the center of the oven, can reduce the risk of localized overheating.

Sometimes other environmental circumstances can have an effect on those colored oxides. The color references work correctly in a perfect world. It would be better to have alternate methods of checking your tempering temps.

150 degrees is WAY! too hot for Parks 50. It is the speed of water/brine quenching at basically "room" temperature. I try to never let mine get over 100 and shoot for about 90 degrees.

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Sometimes other environmental circumstances can have an effect on those colored oxides. The color references work correctly in a perfect world. It would be better to have alternate methods of checking your tempering temps.

150 degrees is WAY! too hot for Parks 50. It is the speed of water/brine quenching at basically "room" temperature. I try to never let mine get over 100 and shoot for about 90 degrees.

Thank you men! I remember reading heat parks to 150 degrees somewhere, I will tone it down to 90. So the blade in question now seems to hard for it to take an edge. Do I reheat, quench again, and temper over? Or should I try to temper at a lower temperature and or duration?

If it's too hard you shouldn't need to re harden. You should draw it again. At a HIGHER temperature, not lower. Just raise the oven temp by 25 degrees and re test. Repeat until you are happy that it's right.

Are you tempering in a Paragon, Evenheat or similar oven, or is it your home kitchen oven?

I only ask because the home electric kitchen oven, while adequate, is not as stable as an oven made specifically for this purpose. I know several makers that use their home ovens, and get consistent and reliable results, but they have two oven thermometers and adjust temp for an average. They also use a tray filled with sand and the blade buried in the sand to create a more stable heat field around the blade eliminating the hot spot variable.

That's a very good trick Joshua.

Thank you all for the information, the blade in question now has a nice edge on it. I did use sand method mention above, and tempered it first 25 degrees higher and then again 50 degrees higher. The blade went from junk to hair shaving sharp. Thank again!

Another satisfied customer!

Glad that worked for you Dean.