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They make a range of ILD’s that companies can choose from (and of course different layer thicknesses will also make a significant difference in how soft or firm a mattress feels as well. You can see the different ILD ranges that Radium supplies here.
There is more about the differences between Talalay and Dunlop in post #7 here. One isn’t inherently any better than the other and the choice between them would be a preference choice rather than a “better/worse” choice. The best way to know which type or blend of latex or the combination of layer thicknesses or firmnesses you tend to prefer will be based on your own personal experience.
ILD is only one of several specs that makes a layer feel softer or firmer than another (see post #4 here and post #2 here) and the ILD of different materials or different types and blends of latex also aren’t always directly comparable to each other (see post #6 here) so using ILD by itself as a reliable indication of how any mattress will “feel” for you can sometimes be misleading.
The properties or “feel” of thicker layers and/or layers that are closer to the surface will be more noticeable than thinner layers or layers that are deeper in a mattress.
Unless you have a great deal of knowledge and experience with different types of mattress materials and specs and different layering combinations and how they combine together and can translate them into your own “real life” experience that can be unique to you or a small percentage of people overall … I would tend to avoid using individual specs such as layer thicknesses or ILD numbers or other complex combinations of specifications to try and predict how a mattress will feel or perform for you and focus more on your own actual testing and/or personal experience. When you try and choose a mattress based on complex combinations of specs that you don’t fully understand then the most common outcome is information overload and “paralysis by analysis”. Choosing a mattress based on complex specs would be among the least reliable ways to choose a suitable mattress.
When you are testing a mattress locally your body will tell you what you need to know about whether a mattress is a good “match” for you in terms of comfort and PPP and complex combinations of “comfort specs” such as ILD are much to complex to use as the basis for deciding whether a mattress will be suitable for you to sleep on.
While your own careful testing or personal experience is the most reliable way to know whether a mattress is a good “match” for you in terms of comfort and PPP … when you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc) and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
Phoenix