This paper presents a method for quantitative differential phase-contrast (DPC) imaging using conventional X-ray tubes, which is compatible with standard absorption radiography. The method employs a three-grating setup, consisting of a source grating (G0), a phase grating (G1), and an analyser absorption grating (G2). This setup allows for the retrieval of quantitative phase images with low-brilliance X-ray sources, such as X-ray tubes, without requiring spatial or temporal coherence. The method is mechanically robust and can be scaled to large fields of view. It provides all the benefits of phase-sensitive imaging while being fully compatible with conventional absorption radiography. The method is applicable to X-ray medical imaging, industrial non-destructive testing, and other low-brilliance radiation sources, such as neutrons or atoms. In conventional X-ray imaging, contrast is obtained through differences in absorption cross-sections. However, for tissues with similar absorption cross-sections, X-ray absorption contrast is poor. To overcome this, several methods have been developed to generate contrast from phase shifts of X-rays. These methods include interferometric methods, techniques using an analyser, and free-space propagation methods. However, these methods require high coherence and are impractical with low-brilliance X-ray sources. The three-grating setup allows for the retrieval of quantitative phase images with low-brilliance X-ray sources. The source grating creates an array of individually coherent, but mutually incoherent sources. The phase grating and analyser absorption grating are used to detect the phase shift of the object. The method is compatible with conventional absorption radiography and allows for the simultaneous retrieval of absorption and phase-contrast images. The method has been tested on a reference sample containing spheres made of PTFE and PMMA, and the results show that the method can accurately measure the absorption and phase shift of the object. The method has also been tested on a small fish, where it successfully retrieved detailed information about the soft tissue structure. The method is promising for clinical applications, particularly in the detection of soft tissue pathologies. It is also applicable to other low-brilliance radiation sources, such as neutrons or atoms. The method is simple to implement and can be used with standard X-ray tubes, making it a practical solution for phase imaging. The method is also resistant to mechanical instabilities and can be used with detectors that have large pixels and a large field of view. The results show that the method can potentially reduce the radiation dose by using higher X-ray energies. The method opens the way for phase-imaging experiments using other forms of radiation, such as neutrons or atoms.This paper presents a method for quantitative differential phase-contrast (DPC) imaging using conventional X-ray tubes, which is compatible with standard absorption radiography. The method employs a three-grating setup, consisting of a source grating (G0), a phase grating (G1), and an analyser absorption grating (G2). This setup allows for the retrieval of quantitative phase images with low-brilliance X-ray sources, such as X-ray tubes, without requiring spatial or temporal coherence. The method is mechanically robust and can be scaled to large fields of view. It provides all the benefits of phase-sensitive imaging while being fully compatible with conventional absorption radiography. The method is applicable to X-ray medical imaging, industrial non-destructive testing, and other low-brilliance radiation sources, such as neutrons or atoms. In conventional X-ray imaging, contrast is obtained through differences in absorption cross-sections. However, for tissues with similar absorption cross-sections, X-ray absorption contrast is poor. To overcome this, several methods have been developed to generate contrast from phase shifts of X-rays. These methods include interferometric methods, techniques using an analyser, and free-space propagation methods. However, these methods require high coherence and are impractical with low-brilliance X-ray sources. The three-grating setup allows for the retrieval of quantitative phase images with low-brilliance X-ray sources. The source grating creates an array of individually coherent, but mutually incoherent sources. The phase grating and analyser absorption grating are used to detect the phase shift of the object. The method is compatible with conventional absorption radiography and allows for the simultaneous retrieval of absorption and phase-contrast images. The method has been tested on a reference sample containing spheres made of PTFE and PMMA, and the results show that the method can accurately measure the absorption and phase shift of the object. The method has also been tested on a small fish, where it successfully retrieved detailed information about the soft tissue structure. The method is promising for clinical applications, particularly in the detection of soft tissue pathologies. It is also applicable to other low-brilliance radiation sources, such as neutrons or atoms. The method is simple to implement and can be used with standard X-ray tubes, making it a practical solution for phase imaging. The method is also resistant to mechanical instabilities and can be used with detectors that have large pixels and a large field of view. The results show that the method can potentially reduce the radiation dose by using higher X-ray energies. The method opens the way for phase-imaging experiments using other forms of radiation, such as neutrons or atoms.